Browse Source

PSU

master
Your Name 1 year ago
parent
commit
79410f01d2
31 changed files with 628 additions and 0 deletions
  1. BIN
      Beaglebone_Blacks/datasheets/am3358.pdf
  2. BIN
      Beaglebone_Blacks/datasheets/sn74lvc2g241.pdf
  3. BIN
      Beaglebone_Blacks/datasheets/tps2051.pdf
  4. +121
    -0
      Beaglebone_Blacks/docs/notes
  5. BIN
      Beaglebone_Blacks/movies/DSCN2367.webm
  6. BIN
      Beaglebone_Blacks/pics/DSCN2422.JPG
  7. +1
    -0
      Beaglebone_Blacks/resources/BeagleBone-Black
  8. BIN
      Beaglebone_Blacks/resources/PCB Layout and Gerber/BeagleBoardBlack_PCB(Allegro and Gerbers).zip
  9. BIN
      Beaglebone_Blacks/resources/PCB Layout and Gerber/BeagleBoardBlack_RevA5_Altium.zip
  10. BIN
      Beaglebone_Blacks/resources/PCB Layout and Gerber/Mentor_BeagleBoardBlack_A5C.zip
  11. BIN
      Beaglebone_Blacks/resources/tps65217.pdf
  12. +13
    -0
      Commodore_1902A_Monitor/docs/11.aux
  13. +243
    -0
      Commodore_1902A_Monitor/docs/11.log
  14. BIN
      Commodore_1902A_Monitor/docs/11.pdf
  15. +112
    -0
      Commodore_1902A_Monitor/docs/11.tex
  16. +109
    -0
      Commodore_1902A_Monitor/docs/11.tex~
  17. +7
    -0
      Commodore_1902A_Monitor/docs/11.toc
  18. +22
    -0
      Dell_Optiplex_780/docs/notes
  19. BIN
      Dell_Optiplex_780/movies/DSCN2452.webm
  20. BIN
      Dell_Optiplex_780/movies/DSCN2453.webm
  21. BIN
      Dell_Optiplex_780/movies/DSCN2454.webm
  22. BIN
      Dell_Optiplex_780/movies/DSCN2455.webm
  23. BIN
      Dell_Optiplex_780/pics/DSCN2447.JPG
  24. BIN
      Dell_Optiplex_780/pics/DSCN2448.JPG
  25. BIN
      Dell_Optiplex_780/pics/DSCN2449.JPG
  26. BIN
      Dell_Optiplex_780/pics/DSCN2450.JPG
  27. BIN
      Dell_Optiplex_780/pics/DSCN2451.JPG
  28. BIN
      Dell_Optiplex_780/pics/atxps_pavouk_org.png
  29. BIN
      Vizio_LED_TV_SolderRepair/movies/DSCN2176.webm
  30. BIN
      Vizio_LED_TV_SolderRepair/movies/DSCN2177.webm
  31. BIN
      Vizio_LED_TV_SolderRepair/movies/DSCN2178.webm

BIN
Beaglebone_Blacks/datasheets/am3358.pdf View File


BIN
Beaglebone_Blacks/datasheets/sn74lvc2g241.pdf View File


BIN
Beaglebone_Blacks/datasheets/tps2051.pdf View File


+ 121
- 0
Beaglebone_Blacks/docs/notes View File

@ -0,0 +1,121 @@
took a look at this
may be power regulator
or may be something downstream
it turns off for a second, then turns off.
hard to tell what is the problem.
need to check all voltage rails when this is powered on.
note that I found you can hit the power button to activate the vreg. but
this might be dangerous to hit repeatedly.
let's try replacing the vreg, as I want an excuse to use my hot air station
it's possible someone just gave it too much power.
https://www.eevblog.com/forum/repair/could-i-repair-a-beaglebone-black-that-had-was-fried-by-the-wrong-adapter/
hehe, they say don't bother fixing. Wow...
Steps for this:
Attempt replacement of vreg
if that doesn't solve it, likely something downstream.
connect to power rails, with PSU, and watch what heats up with iso alcohol.
I have 4 or 5 of these beagles, so I only need to find it once. In fact, maybe
I should just skip to the inserting the Power supply in. there are a few 0805
caps that are relatively easy to tap into...
The board files are allegro, and I don't run win but
the schematic shows cap labels, so this is probably the best plan of attack.
If I don't find anything heating up, then it would point to the power supply...
Let's do that.
EDIT: testing all 4 beagles
1 works, it appears.
1 turns on all 4 status leds, but no blinks.
2 have a brief led light on power reg, but then off. protection circuitry.
I found 1 of them with a blown resistor on the ethernet shield to digital ground.
it was a 0.1 ohm resistor.
I found 2 of the 2 with brief led lights to have a cap (3.3v rail) at 12 ohms. The others
are 400 ohms. This was mentioned on forum. Probably someone put 12v on the input, and blew the 10v
caps... flawed design, i think.
I'm going to remove those caps first. off to the hot air station
i should buy some 10uf 0805. i only have through hole and 1uf 0805 (though in a project
bag there might be one somewhere...)
After replacing cap, there's still 12 and 5 ohms on those respectively.
So it wasn't the caps, but something on the rail. Looks like the 3v3 rail is the only
rail that has the short, per the other caps, didn't give me any unusual resistance, and
also 3v3 is the one you would expect to be shorted (main v rail).
can't find c16, which is on rtc. I need allegro to do layout searching
3v3 goes into
main CPU (arctic)
usb host tps2051
SPI board id
24lc32
lan adapter (3v3b)
HDMI (3v3b)
and some 74 logic.
I think the cpu is the issue. Let's disconnect R14, and see if power rail boots.
there's two inputs. one is where r14 is, another is on USB. Hopefully I don't
have to track down usb input. don't have layout.
removed R52, and R14, but it's still shorted.
I believe the USB input to CPU is causing this. There aren't many other things it could be
EDIT: looks like the 74 logic here is max 6.5 volts or so. could also be that.
lets try to track down the short with the 6 digit dmm
NOTE: there are two distinct 3v3 rails a and b
3v3B comes from TL5209
that is enabled after 3v3A is turned on. (see notes in schematic updates)
C20 on 3v3b looks to be 0.4K ohms, so OK.
Must be 3v3a, which doesn't have much.
Nice idea, to separate 3v3 rails.
based on my tracking with the 6 ohm dmm
i found the lowest resistance somewhere around 5.5ohms in between the cpu and the ddr
the ddr is 3v3b, so it must be the cpu.
let's remove hte cpu, and see if power rails start.
removed CPU. first bga removal for me.
And sucess. The low resistance on C16 is now 0.4K ohms. So the CPU is the weak point.
I guess this means by design, of the bbb, I will be doing some hot air bga soldering.
it must be gods will. (ti's will)
I removed the second bga, but this time, I pulled some pads. Of course you can
pull pads on a bga... May not be repairable, but lesson learned.

BIN
Beaglebone_Blacks/movies/DSCN2367.webm View File


BIN
Beaglebone_Blacks/pics/DSCN2422.JPG View File

Before After
Width: 800  |  Height: 600  |  Size: 160 KiB

+ 1
- 0
Beaglebone_Blacks/resources/BeagleBone-Black

@ -0,0 +1 @@
Subproject commit 29f53596a2d88222e65fe19a7434f78d18c18711

BIN
Beaglebone_Blacks/resources/PCB Layout and Gerber/BeagleBoardBlack_PCB(Allegro and Gerbers).zip View File


BIN
Beaglebone_Blacks/resources/PCB Layout and Gerber/BeagleBoardBlack_RevA5_Altium.zip View File


BIN
Beaglebone_Blacks/resources/PCB Layout and Gerber/Mentor_BeagleBoardBlack_A5C.zip View File


BIN
Beaglebone_Blacks/resources/tps65217.pdf View File


+ 13
- 0
Commodore_1902A_Monitor/docs/11.aux View File

@ -0,0 +1,13 @@
\relax
\@writefile{lof}{\contentsline {figure}{\numberline {1}{\ignorespaces Commodore 1902A 14'' CRT Monitor\relax }}{1}}
\@writefile{toc}{\contentsline {section}{\numberline {1}Overview}{1}}
\@writefile{toc}{\contentsline {section}{\numberline {2}Work Log}{2}}
\@writefile{toc}{\contentsline {subsection}{\numberline {2.1}We require more resources... (Starcraft 2 reference)}{2}}
\@writefile{lof}{\contentsline {figure}{\numberline {2}{\ignorespaces Computer Monitor Troubleshooting and Repair\relax }}{3}}
\@writefile{lof}{\contentsline {figure}{\numberline {3}{\ignorespaces Second Page. Right from the start the book is easy to read and approachable.\relax }}{4}}
\@writefile{toc}{\contentsline {subsection}{\numberline {2.2}Errors on the Schematic}{4}}
\@writefile{lof}{\contentsline {figure}{\numberline {4}{\ignorespaces Schematic lists ICs with numbers that...\relax }}{5}}
\@writefile{lof}{\contentsline {figure}{\numberline {5}{\ignorespaces Differ on the actual layout diagram. Repairman beware!\relax }}{5}}
\@writefile{toc}{\contentsline {subsection}{\numberline {2.3}Getting the Monitor ready for the repair attempt}{6}}
\@writefile{toc}{\contentsline {subsection}{\numberline {2.4}Repair Attempt}{6}}
\@writefile{toc}{\contentsline {section}{\numberline {3}References}{6}}

+ 243
- 0
Commodore_1902A_Monitor/docs/11.log View File

@ -0,0 +1,243 @@
This is pdfTeX, Version 3.14159265-2.6-1.40.15 (TeX Live 2015/dev/Debian) (preloaded format=pdflatex 2018.11.28) 20 JUL 2019 02:53
entering extended mode
restricted \write18 enabled.
%&-line parsing enabled.
**/home/layoutdev/Desktop/code/documentation_general/Repairs_2019/Commodore_190
2A_Monitor/docs/11.tex
(/home/layoutdev/Desktop/code/documentation_general/Repairs_2019/Commodore_1902
A_Monitor/docs/11.tex
LaTeX2e <2014/05/01>
Babel <3.9l> and hyphenation patterns for 2 languages loaded.
(/usr/share/texlive/texmf-dist/tex/latex/base/article.cls
Document Class: article 2014/09/29 v1.4h Standard LaTeX document class
(/usr/share/texlive/texmf-dist/tex/latex/base/size11.clo
File: size11.clo 2014/09/29 v1.4h Standard LaTeX file (size option)
)
\c@part=\count79
\c@section=\count80
\c@subsection=\count81
\c@subsubsection=\count82
\c@paragraph=\count83
\c@subparagraph=\count84
\c@figure=\count85
\c@table=\count86
\abovecaptionskip=\skip41
\belowcaptionskip=\skip42
\bibindent=\dimen102
)
(/usr/share/texlive/texmf-dist/tex/latex/graphics/graphicx.sty
Package: graphicx 2014/04/25 v1.0g Enhanced LaTeX Graphics (DPC,SPQR)
(/usr/share/texlive/texmf-dist/tex/latex/graphics/keyval.sty
Package: keyval 2014/05/08 v1.15 key=value parser (DPC)
\KV@toks@=\toks14
)
(/usr/share/texlive/texmf-dist/tex/latex/graphics/graphics.sty
Package: graphics 2009/02/05 v1.0o Standard LaTeX Graphics (DPC,SPQR)
(/usr/share/texlive/texmf-dist/tex/latex/graphics/trig.sty
Package: trig 1999/03/16 v1.09 sin cos tan (DPC)
)
(/usr/share/texlive/texmf-dist/tex/latex/latexconfig/graphics.cfg
File: graphics.cfg 2010/04/23 v1.9 graphics configuration of TeX Live
)
Package graphics Info: Driver file: pdftex.def on input line 91.
(/usr/share/texlive/texmf-dist/tex/latex/pdftex-def/pdftex.def
File: pdftex.def 2011/05/27 v0.06d Graphics/color for pdfTeX
(/usr/share/texlive/texmf-dist/tex/generic/oberdiek/infwarerr.sty
Package: infwarerr 2010/04/08 v1.3 Providing info/warning/error messages (HO)
)
(/usr/share/texlive/texmf-dist/tex/generic/oberdiek/ltxcmds.sty
Package: ltxcmds 2011/11/09 v1.22 LaTeX kernel commands for general use (HO)
)
\Gread@gobject=\count87
))
\Gin@req@height=\dimen103
\Gin@req@width=\dimen104
)
(/usr/share/texlive/texmf-dist/tex/latex/caption/caption.sty
Package: caption 2013/05/02 v3.3-89 Customizing captions (AR)
(/usr/share/texlive/texmf-dist/tex/latex/caption/caption3.sty
Package: caption3 2013/05/02 v1.6-88 caption3 kernel (AR)
Package caption3 Info: TeX engine: e-TeX on input line 57.
\captionmargin=\dimen105
\captionmargin@=\dimen106
\captionwidth=\dimen107
\caption@tempdima=\dimen108
\caption@indent=\dimen109
\caption@parindent=\dimen110
\caption@hangindent=\dimen111
)
\c@ContinuedFloat=\count88
) (./11.aux)
\openout1 = `11.aux'.
LaTeX Font Info: Checking defaults for OML/cmm/m/it on input line 9.
LaTeX Font Info: ... okay on input line 9.
LaTeX Font Info: Checking defaults for T1/cmr/m/n on input line 9.
LaTeX Font Info: ... okay on input line 9.
LaTeX Font Info: Checking defaults for OT1/cmr/m/n on input line 9.
LaTeX Font Info: ... okay on input line 9.
LaTeX Font Info: Checking defaults for OMS/cmsy/m/n on input line 9.
LaTeX Font Info: ... okay on input line 9.
LaTeX Font Info: Checking defaults for OMX/cmex/m/n on input line 9.
LaTeX Font Info: ... okay on input line 9.
LaTeX Font Info: Checking defaults for U/cmr/m/n on input line 9.
LaTeX Font Info: ... okay on input line 9.
(/usr/share/texlive/texmf-dist/tex/context/base/supp-pdf.mkii
[Loading MPS to PDF converter (version 2006.09.02).]
\scratchcounter=\count89
\scratchdimen=\dimen112
\scratchbox=\box26
\nofMPsegments=\count90
\nofMParguments=\count91
\everyMPshowfont=\toks15
\MPscratchCnt=\count92
\MPscratchDim=\dimen113
\MPnumerator=\count93
\makeMPintoPDFobject=\count94
\everyMPtoPDFconversion=\toks16
) (/usr/share/texlive/texmf-dist/tex/generic/oberdiek/pdftexcmds.sty
Package: pdftexcmds 2011/11/29 v0.20 Utility functions of pdfTeX for LuaTeX (HO
)
(/usr/share/texlive/texmf-dist/tex/generic/oberdiek/ifluatex.sty
Package: ifluatex 2010/03/01 v1.3 Provides the ifluatex switch (HO)
Package ifluatex Info: LuaTeX not detected.
)
(/usr/share/texlive/texmf-dist/tex/generic/oberdiek/ifpdf.sty
Package: ifpdf 2011/01/30 v2.3 Provides the ifpdf switch (HO)
Package ifpdf Info: pdfTeX in PDF mode is detected.
)
Package pdftexcmds Info: LuaTeX not detected.
Package pdftexcmds Info: \pdf@primitive is available.
Package pdftexcmds Info: \pdf@ifprimitive is available.
Package pdftexcmds Info: \pdfdraftmode found.
)
(/usr/share/texlive/texmf-dist/tex/latex/oberdiek/epstopdf-base.sty
Package: epstopdf-base 2010/02/09 v2.5 Base part for package epstopdf
(/usr/share/texlive/texmf-dist/tex/latex/oberdiek/grfext.sty
Package: grfext 2010/08/19 v1.1 Manage graphics extensions (HO)
(/usr/share/texlive/texmf-dist/tex/generic/oberdiek/kvdefinekeys.sty
Package: kvdefinekeys 2011/04/07 v1.3 Define keys (HO)
))
(/usr/share/texlive/texmf-dist/tex/latex/oberdiek/kvoptions.sty
Package: kvoptions 2011/06/30 v3.11 Key value format for package options (HO)
(/usr/share/texlive/texmf-dist/tex/generic/oberdiek/kvsetkeys.sty
Package: kvsetkeys 2012/04/25 v1.16 Key value parser (HO)
(/usr/share/texlive/texmf-dist/tex/generic/oberdiek/etexcmds.sty
Package: etexcmds 2011/02/16 v1.5 Avoid name clashes with e-TeX commands (HO)
Package etexcmds Info: Could not find \expanded.
(etexcmds) That can mean that you are not using pdfTeX 1.50 or
(etexcmds) that some package has redefined \expanded.
(etexcmds) In the latter case, load this package earlier.
)))
Package grfext Info: Graphics extension search list:
(grfext) [.png,.pdf,.jpg,.mps,.jpeg,.jbig2,.jb2,.PNG,.PDF,.JPG,.JPE
G,.JBIG2,.JB2,.eps]
(grfext) \AppendGraphicsExtensions on input line 452.
(/usr/share/texlive/texmf-dist/tex/latex/latexconfig/epstopdf-sys.cfg
File: epstopdf-sys.cfg 2010/07/13 v1.3 Configuration of (r)epstopdf for TeX Liv
e
))
Package caption Info: Begin \AtBeginDocument code.
Package caption Info: End \AtBeginDocument code.
<../pics/DSCN1699.JPG, id=1, 803.0pt x 602.25pt>
File: ../pics/DSCN1699.JPG Graphic file (type jpg)
<use ../pics/DSCN1699.JPG>
Package pdftex.def Info: ../pics/DSCN1699.JPG used on input line 17.
(pdftex.def) Requested size: 321.1943pt x 240.89572pt.
Package caption Warning: \captionsetup{type*=...} or \captionof
(caption) outside box or environment on input line 18.
See the caption package documentation for explanation.
LaTeX Font Info: External font `cmex10' loaded for size
(Font) <10.95> on input line 21.
LaTeX Font Info: External font `cmex10' loaded for size
(Font) <8> on input line 21.
LaTeX Font Info: External font `cmex10' loaded for size
(Font) <6> on input line 21.
LaTeX Font Info: External font `cmex10' loaded for size
(Font) <9> on input line 21.
LaTeX Font Info: External font `cmex10' loaded for size
(Font) <5> on input line 21.
(./11.toc [1
{/var/lib/texmf/fonts/map/pdftex/updmap/pdftex.map} <../pics/DSCN1699.JPG>])
\tf@toc=\write3
\openout3 = `11.toc'.
[2] <../pics/DSCN1864.JPG, id=16, 803.0pt x 602.25pt>
File: ../pics/DSCN1864.JPG Graphic file (type jpg)
<use ../pics/DSCN1864.JPG>
Package pdftex.def Info: ../pics/DSCN1864.JPG used on input line 54.
(pdftex.def) Requested size: 321.1943pt x 240.89572pt.
[3 <../pics/DSCN1864.JPG>]
<../pics/DSCN1865.JPG, id=20, 803.0pt x 602.25pt>
File: ../pics/DSCN1865.JPG Graphic file (type jpg)
<use ../pics/DSCN1865.JPG>
Package pdftex.def Info: ../pics/DSCN1865.JPG used on input line 63.
(pdftex.def) Requested size: 321.1943pt x 240.89572pt.
<../pics/DSCN1866.JPG, id=21, 803.0pt x 602.25pt>
File: ../pics/DSCN1866.JPG Graphic file (type jpg)
<use ../pics/DSCN1866.JPG>
Package pdftex.def Info: ../pics/DSCN1866.JPG used on input line 69.
(pdftex.def) Requested size: 321.1943pt x 240.89572pt.
[4 <../pics/DSCN1865.JPG>] <../pics/DSCN1868.JPG, id=25, 192.72pt x 144.54pt>
File: ../pics/DSCN1868.JPG Graphic file (type jpg)
<use ../pics/DSCN1868.JPG>
Package pdftex.def Info: ../pics/DSCN1868.JPG used on input line 73.
(pdftex.def) Requested size: 321.84123pt x 241.3809pt.
[5 <../pics/DSCN1866.JPG> <../pics/DSCN1868.JPG>]
LaTeX Font Info: Try loading font information for OMS+cmr on input line 95.
(/usr/share/texlive/texmf-dist/tex/latex/base/omscmr.fd
File: omscmr.fd 2014/09/29 v2.5h Standard LaTeX font definitions
)
LaTeX Font Info: Font shape `OMS/cmr/m/n' in size <10.95> not available
(Font) Font shape `OMS/cmsy/m/n' tried instead on input line 95.
Underfull \hbox (badness 10000) in paragraph at lines 101--103
[]\OT1/cmr/m/n/10.95 Retro Game Me-chan-ics Ex-plained:
[]
[6] [7] (./11.aux) )
Here is how much of TeX's memory you used:
2588 strings out of 495020
41331 string characters out of 6181323
95798 words of memory out of 5000000
5793 multiletter control sequences out of 15000+600000
8809 words of font info for 31 fonts, out of 8000000 for 9000
14 hyphenation exceptions out of 8191
38i,8n,38p,903b,194s stack positions out of 5000i,500n,10000p,200000b,80000s
</usr/share/texlive/texmf-dist/fonts/type1/public/amsfonts/
cm/cmbx10.pfb></usr/share/texlive/texmf-dist/fonts/type1/public/amsfonts/cm/cmb
x12.pfb></usr/share/texlive/texmf-dist/fonts/type1/public/amsfonts/cm/cmr10.pfb
></usr/share/texlive/texmf-dist/fonts/type1/public/amsfonts/cm/cmr6.pfb></usr/s
hare/texlive/texmf-dist/fonts/type1/public/amsfonts/cm/cmr8.pfb></usr/share/tex
live/texmf-dist/fonts/type1/public/amsfonts/cm/cmr9.pfb></usr/share/texlive/tex
mf-dist/fonts/type1/public/amsfonts/cm/cmsy10.pfb>
Output written on 11.pdf (7 pages, 841177 bytes).
PDF statistics:
61 PDF objects out of 1000 (max. 8388607)
39 compressed objects within 1 object stream
0 named destinations out of 1000 (max. 500000)
26 words of extra memory for PDF output out of 10000 (max. 10000000)

BIN
Commodore_1902A_Monitor/docs/11.pdf View File


+ 112
- 0
Commodore_1902A_Monitor/docs/11.tex View File

@ -0,0 +1,112 @@
\documentclass[11pt]{article}
%Gummi|065|=)
\usepackage{graphicx}
\usepackage{caption}
\title{\textbf{Commodore 1902A Repair}}
\author{Steak Electronics}
\date{}
\begin{document}
%\maketitle
\begin{center}
\textbf{Commodore 1902A Repair}
\end{center}
%\vspace{0.2in}
\includegraphics[scale=0.4]{../pics/DSCN1699.JPG}
\captionof{figure}{Commodore 1902A 14'' CRT Monitor}
\section{Overview}
The goal is to repair an old Commodore CRT monitor. This is not a computer monitor, but a strange hybrid TV/Commodore only mode CRT. Normal CRTs take input of RGB, while this one takes composite video (like a television), as well as RGBI\footnote{This is one of the things I learned here, the difference between a computer monitor and a television. TVs take in NTSC/PAL/SECAM analog video. Computer monitors take in the signals already split up (VGA). However, this monitor does a hybrid of both, being made before VGA was commonplace.}. This particular monitor, the 1902A has three inputs. One for composite, one for S-Video (essentially connected to same circuitry as composite) and one for RGBI mode.
Currently, the monitor has errors on composite input / S-video. There are no errors on the RGBI input.
\tableofcontents
\section{Work Log}
I picked up an old HP TV service manual (6945A) for this project. I am not knowledgable about televisions, but the more I read, the more I think I can handle this. I have also the manual for the monitor, though it is quite a bit sparse, comparably.
\vspace{0.2in}
Quite a bit of the Commodore 1902A TV circuitry (H sync, V sync, etc) is in a few ICs, according to the schematic.
\vspace{0.2in}
The waveforms in the Commodore manual were created with a (standard?) NTSC test signal, the \textbf{10 bar gated rainbow pattern signal}. I am currently researching how to generate that myself, without forking out the cash for a video tester (Cheapest I saw the other day was \$70. I wouldn't pay more than \$20.
\vspace{0.2in}
From a brief search, most people have only setup rough test signals with uCs that do either NTSC or PAL, but not necessarily the full 10 bar gated test signal. Instead only a passable working signal, to verify video output, seems to be par for the course. I might be out of luck!
\vspace{0.2in}
\subsection{We require more resources... (Starcraft 2 reference)}
I reviewed this page:
http://www.repairfaq.org/sam/monfaq.htm\#monsugref
Which many will recognize as the gargantuan repair faq website.\footnote{I find text heavy websites like this, quite incomprehensible, to be honest. How much better the site would be, if it was a book. I know I'm not the only one that thinks this way (e.g. Bill Waterson said he prefers actual paper of his comics to a computer screen), but yet websites continually seem to post article after article, after blogpost, after blogpost, of which I will not take the time to click through. Websites are infinitely inferior to books, for any significant amount of text. This is why twitter (and not booker) is so successful. Am I wrong in thinking this, or are the search engines skewing how much people actually read these ``blog'' websites?} I'm going to purchase a book they mention:\\
\textbf{Computer Monitor Troubleshooting and Repair} - Joe Desposito and Kevin Garabedian
\includegraphics[scale=0.4]{../pics/DSCN1864.JPG}
\captionof{figure}{Computer Monitor Troubleshooting and Repair}
which cost me a whole \$6.00 from a used book store online. While the HP book was helpful, it is for a B\&W CRT lacking any colour related circuitry, and I need something with more practical repair advice. The HP tech book, is also dry, which means it assumes you understand a lot of the mechanics already.
After reading some pages of the computer monitor repair book (recommended as I said by repairfaq.org) I can say it is a good book, and would recommend it to others. it lacks any concrete material on TV Signal encode/decoding, it being a book on computer monitors (which have RGB signals split up by default, via the VGA connector), it remains a straightforward and down to earth book on CRTs. An obsolete gem. The book uses three computer monitor schematics for its instructions, showing different approaches to similar circuits. A schematic for a Magnavox, NEC, and Samtron VGA Computer monitor are covered in explicit detail.
Here's an example page, for those readers interested in a preview:
\includegraphics[scale=0.4]{../pics/DSCN1865.JPG}
\captionof{figure}{Second Page. Right from the start the book is easy to read and approachable.}
\subsection{Errors on the Schematic}
After reviewing the Commodore 1902A service manual, I noticed that the layout design doesn't match up 1:1 with the schematic... On the same service manual! Is this an honest mistake, or a reluctance to give repairmen the real schematic, or a limitation of time and money? Who knows. In any case, I found an intial error looking at the early Composite signal input.
\includegraphics[scale=0.4]{../pics/DSCN1866.JPG}
\captionof{figure}{Schematic lists ICs with numbers that...}
\includegraphics[scale=1.67]{../pics/DSCN1868.JPG}
\captionof{figure}{Differ on the actual layout diagram. Repairman beware!}
\subsection{Getting the Monitor ready for the repair attempt}
I setup the monitor on the bench this evening, desoldering the can on the bottom, and resoldering on of the hi voltage wires I had to cut in order to disassemble it. The pictures I took helped a lot in finding where everything went. In particular there are two ground pins that are easily confused. One is for the high voltage area, the other for the CRT board.
\vspace{0.2in}
Reviewing the schematic, I traced out a bit more of what goes where, and will start by checking the voltage levels. But first, to get a signal source.
\vspace{0.2in}
Like the Sony PVM\footnote{Sony PVMs are a brand of television that retro video game players make a big fuss about (circa 2010's). To be honest, I have 2 of them, and I don't find them worth the hype. Especially not RGB mode. Any modest CRT was good enough when you were a kid, and any modest CRT is good enough as an adult. It's the gameplay that matters. Don't believe the hype!} I've taken apart and attempted to repair previously, this CRT is not easy to service. Accessing the bottom of the board while it's powered on is a balancing act. But I have managed to get it on the bench, and after reading a bit more of the Computer Monitor Troubleshooting and Repair book, (and possibly a separate book dedicated for Television, to cover the decoding) I will start the repair.
\subsection{Repair Attempt}
I plugged a PS1 into the television, to find that the picture was working.
\section{References}
\textbf{Books}
\begin{itemize}
\item Art of Electronics 3rd Edition (Horowitz, Hill): Appendix I - Television.
\item Computer Monitor Troubleshooting and Repair - Joe Desposito and Kevin Garabedian
\end{itemize}
\textbf{Video}\footnote{Disclaimer: Youtube is bad. Please avoid when possible in favor of a video site that is not a centralized, censored, monopoly.}
\begin{itemize}
\item Retro Game Mechanics Explained: https://www.youtube.com/channel/UCwRqWnW5ZkVaP\_lZF7caZ-g
\\(the SNES section has some well produced CRT video explanations).
\end{itemize}
\end{document}

+ 109
- 0
Commodore_1902A_Monitor/docs/11.tex~ View File

@ -0,0 +1,109 @@
\documentclass[11pt]{article}
%Gummi|065|=)
\usepackage{graphicx}
\usepackage{caption}
\title{\textbf{Commodore 1902A Repair}}
\author{Steak Electronics}
\date{}
\begin{document}
%\maketitle
\begin{center}
\textbf{Commodore 1902A Repair}
\end{center}
%\vspace{0.2in}
\includegraphics[scale=0.4]{../pics/DSCN1699.JPG}
\captionof{figure}{Commodore 1902A 14'' CRT Monitor}
\section{Overview}
The goal is to repair an old Commodore CRT monitor. This is not a computer monitor, but a strange hybrid TV/Commodore only mode CRT. Normal CRTs take input of RGB, while this one takes composite video (like a television), as well as RGBI\footnote{This is one of the things I learned here, the difference between a computer monitor and a television. TVs take in NTSC/PAL/SECAM analog video. Computer monitors take in the signals already split up (VGA). However, this monitor does a hybrid of both, being made before VGA was commonplace.}. This particular monitor, the 1902A has three inputs. One for composite, one for S-Video (essentially connected to same circuitry as composite) and one for RGBI mode.
Currently, the monitor has errors on composite input / S-video. There are no errors on the RGBI input.
\tableofcontents
\section{Work Log}
I picked up an old HP TV service manual (6945A) for this project. I am not knowledgable about televisions, but the more I read, the more I think I can handle this. I have also the manual for the monitor, though it is quite a bit sparse, comparably.
\vspace{0.2in}
Quite a bit of the Commodore 1902A TV circuitry (H sync, V sync, etc) is in a few ICs, according to the schematic.
\vspace{0.2in}
The waveforms in the Commodore manual were created with a (standard?) NTSC test signal, the \textbf{10 bar gated rainbow pattern signal}. I am currently researching how to generate that myself, without forking out the cash for a video tester (Cheapest I saw the other day was \$70. I wouldn't pay more than \$20.
\vspace{0.2in}
From a brief search, most people have only setup rough test signals with uCs that do either NTSC or PAL, but not necessarily the full 10 bar gated test signal. Instead only a passable working signal, to verify video output, seems to be par for the course. I might be out of luck!
\vspace{0.2in}
\subsection{We require more resources... (Starcraft 2 reference)}
I reviewed this page:
http://www.repairfaq.org/sam/monfaq.htm\#monsugref
Which many will recognize as the gargantuan repair faq website.\footnote{I find text heavy websites like this, quite incomprehensible, to be honest. How much better the site would be, if it was a book. I know I'm not the only one that thinks this way (e.g. Bill Waterson said he prefers actual paper of his comics to a computer screen), but yet websites continually seem to post article after article, after blogpost, after blogpost, of which I will not take the time to click through. Websites are infinitely inferior to books, for any significant amount of text. This is why twitter (and not booker) is so successful. Am I wrong in thinking this, or are the search engines skewing how much people actually read these ``blog'' websites?} I'm going to purchase a book they mention:\\
\textbf{Computer Monitor Troubleshooting and Repair} - Joe Desposito and Kevin Garabedian
\includegraphics[scale=0.4]{../pics/DSCN1864.JPG}
\captionof{figure}{Computer Monitor Troubleshooting and Repair}
which cost me a whole \$6.00 from a used book store online. While the HP book was helpful, it is for a B\&W CRT lacking any colour related circuitry, and I need something with more practical repair advice. The HP tech book, is also dry, which means it assumes you understand a lot of the mechanics already.
After reading some pages of the computer monitor repair book (recommended as I said by repairfaq.org) I can say it is a good book, and would recommend it to others. it lacks any concrete material on TV Signal encode/decoding, it being a book on computer monitors (which have RGB signals split up by default, via the VGA connector), it remains a straightforward and down to earth book on CRTs. An obsolete gem. The book uses three computer monitor schematics for its instructions, showing different approaches to similar circuits. A schematic for a Magnavox, NEC, and Samtron VGA Computer monitor are covered in explicit detail.
Here's an example page, for those readers interested in a preview:
\includegraphics[scale=0.4]{../pics/DSCN1865.JPG}
\captionof{figure}{Second Page. Right from the start the book is easy to read and approachable.}
\subsection{Errors on the Schematic}
After reviewing the Commodore 1902A service manual, I noticed that the layout design doesn't match up 1:1 with the schematic... On the same service manual! Is this an honest mistake, or a reluctance to give repairmen the real schematic, or a limitation of time and money? Who knows. In any case, I found an intial error looking at the early Composite signal input.
\includegraphics[scale=0.4]{../pics/DSCN1866.JPG}
\captionof{figure}{Schematic lists ICs with numbers that...}
\includegraphics[scale=1.67]{../pics/DSCN1868.JPG}
\captionof{figure}{Differ on the actual layout diagram. Repairman beware!}
\subsection{Getting the Monitor ready for the repair attempt}
I setup the monitor on the bench this evening, desoldering the can on the bottom, and resoldering on of the hi voltage wires I had to cut in order to disassemble it. The pictures I took helped a lot in finding where everything went. In particular there are two ground pins that are easily confused. One is for the high voltage area, the other for the CRT board.
\vspace{0.2in}
Reviewing the schematic, I traced out a bit more of what goes where, and will start by checking the voltage levels. But first, to get a signal source.
\vspace{0.2in}
Like the Sony PVM\footnote{Sony PVMs are a brand of television that retro video game players make a big fuss about (circa 2010's). To be honest, I have 2 of them, and I don't find them worth the hype. Especially not RGB mode. Any modest CRT was good enough when you were a kid, and any modest CRT is good enough as an adult. It's the gameplay that matters. Don't believe the hype!} I've taken apart and attempted to repair previously, this CRT is not easy to service. Accessing the bottom of the board while it's powered on is a balancing act. But I have managed to get it on the bench, and after reading a bit more of the Computer Monitor Troubleshooting and Repair book, (and possibly a separate book dedicated for Television, to cover the decoding) I will start the repair.
\section{References}
\textbf{Books}
\begin{itemize}
\item Art of Electronics 3rd Edition (Horowitz, Hill): Appendix I - Television.
\item Computer Monitor Troubleshooting and Repair - Joe Desposito and Kevin Garabedian
\end{itemize}
\textbf{Video}\footnote{Disclaimer: Youtube is bad. Please avoid when possible in favor of a video site that is not a centralized, censored, monopoly.}
\begin{itemize}
\item Retro Game Mechanics Explained: https://www.youtube.com/channel/UCwRqWnW5ZkVaP\_lZF7caZ-g
\\(the SNES section has some well produced CRT video explanations).
\end{itemize}
\end{document}

+ 7
- 0
Commodore_1902A_Monitor/docs/11.toc View File

@ -0,0 +1,7 @@
\contentsline {section}{\numberline {1}Overview}{1}
\contentsline {section}{\numberline {2}Work Log}{2}
\contentsline {subsection}{\numberline {2.1}We require more resources... (Starcraft 2 reference)}{2}
\contentsline {subsection}{\numberline {2.2}Errors on the Schematic}{4}
\contentsline {subsection}{\numberline {2.3}Getting the Monitor ready for the repair attempt}{6}
\contentsline {subsection}{\numberline {2.4}Repair Attempt}{6}
\contentsline {section}{\numberline {3}References}{6}

+ 22
- 0
Dell_Optiplex_780/docs/notes View File

@ -0,0 +1,22 @@
Some heat damage on the PSU.
Don't know where the fault is.
-12V rail is -10.6V.
Need to test ATX psu with proper equipment.
Need to replace CPU, and try booting.
Need to see if problem lies in CPU, Motherboard, or PSU.
Not worth my time right now.
Putting aside.
Note: I did check a bit of the ATX PSU. I found a picture at
http://www.pavouk.org/hw/atxps.png
Which shows a similar supply. When in doubt, find a similar schematic.

BIN
Dell_Optiplex_780/movies/DSCN2452.webm View File


BIN
Dell_Optiplex_780/movies/DSCN2453.webm View File


BIN
Dell_Optiplex_780/movies/DSCN2454.webm View File


BIN
Dell_Optiplex_780/movies/DSCN2455.webm View File


BIN
Dell_Optiplex_780/pics/DSCN2447.JPG View File

Before After
Width: 800  |  Height: 600  |  Size: 186 KiB

BIN
Dell_Optiplex_780/pics/DSCN2448.JPG View File

Before After
Width: 800  |  Height: 600  |  Size: 140 KiB

BIN
Dell_Optiplex_780/pics/DSCN2449.JPG View File

Before After
Width: 800  |  Height: 600  |  Size: 182 KiB

BIN
Dell_Optiplex_780/pics/DSCN2450.JPG View File

Before After
Width: 800  |  Height: 600  |  Size: 147 KiB

BIN
Dell_Optiplex_780/pics/DSCN2451.JPG View File

Before After
Width: 800  |  Height: 600  |  Size: 154 KiB

BIN
Dell_Optiplex_780/pics/atxps_pavouk_org.png View File

Before After
Width: 1392  |  Height: 850  |  Size: 25 KiB

BIN
Vizio_LED_TV_SolderRepair/movies/DSCN2176.webm View File


BIN
Vizio_LED_TV_SolderRepair/movies/DSCN2177.webm View File


BIN
Vizio_LED_TV_SolderRepair/movies/DSCN2178.webm View File


Loading…
Cancel
Save