Welcome, Guest. Please login or register.
August 17, 2017, 09:04:25 PM

Login with username, password and session length
* Home Help Arcade Login Register
.
+  Forum
|-+  NLG Members who host their own Repair Logs of Various Games.
| |-+  Channelmaniac's Arcadecomponents' Old School Repair Logs (Moderator: channelmaniac)
| | |-+  Commodore (VIC-20, 64, and 128) Computers
0 Members and 1 Guest are viewing this topic. « previous next »
Pages: [1] Go Down Print
Author Topic: Commodore (VIC-20, 64, and 128) Computers  (Read 13869 times)
channelmaniac
Surface mount soldering geek
Global NLG Site Moderator
Sr.Tech NLG Member 1000+ Post
*

Total Karma Storms: 568
Offline Offline

Gender: Male
Posts: 2127


Few things are better than fixing an old game...


WWW
« on: September 15, 2008, 08:28:34 PM »

Model: Commodore 64
Symptom: Boots normally but all text on screen flashes with random colors

Replace the PLA IC, part # 906114-01 (a.k.a. 82S100). It controls the color RAM (2114 SRAM) access.

If the screen looked normal with the exception of some wrong colored areas of the screen then replace the 2114 SRAM IC.
Logged

I have too many hobbies! Electronics, gunsmithing, Miatas, arcade games, metal detecting, etc...

http://www.arcadecomponents.com
channelmaniac
Surface mount soldering geek
Global NLG Site Moderator
Sr.Tech NLG Member 1000+ Post
*

Total Karma Storms: 568
Offline Offline

Gender: Male
Posts: 2127


Few things are better than fixing an old game...


WWW
« Reply #1 on: September 15, 2008, 08:28:50 PM »

Model: C64
Symptom: Dead, blank screen.

Reset line was stuck low. Found a short between the 7406 IC and the metalized cardboard RFI shield. Attached a thin piece of posterboard to the shield with double-stick tape and trimmed the pin on the IC.
Logged

I have too many hobbies! Electronics, gunsmithing, Miatas, arcade games, metal detecting, etc...

http://www.arcadecomponents.com
channelmaniac
Surface mount soldering geek
Global NLG Site Moderator
Sr.Tech NLG Member 1000+ Post
*

Total Karma Storms: 568
Offline Offline

Gender: Male
Posts: 2127


Few things are better than fixing an old game...


WWW
« Reply #2 on: September 15, 2008, 08:29:07 PM »

Model: C64
Symptom: Dead. Blank screen.

Found multiple machines with this symptom: Replaced bad VIC II chip on one, replaced a bad PLA chip on another, Replaced a bad 74LS629. Could also be caused by a defective crystal. PLA chip is the most common suspect.
Logged

I have too many hobbies! Electronics, gunsmithing, Miatas, arcade games, metal detecting, etc...

http://www.arcadecomponents.com
channelmaniac
Surface mount soldering geek
Global NLG Site Moderator
Sr.Tech NLG Member 1000+ Post
*

Total Karma Storms: 568
Offline Offline

Gender: Male
Posts: 2127


Few things are better than fixing an old game...


WWW
« Reply #3 on: September 15, 2008, 08:29:23 PM »

Model: C64
Symptom: Screen & border showing, but no text

Ran into different causes of this. One machine had a defective 4164 RAM IC, another machine had a defective PLA, and another a bad Character ROM. PLA is the most common cause for this.
Logged

I have too many hobbies! Electronics, gunsmithing, Miatas, arcade games, metal detecting, etc...

http://www.arcadecomponents.com
channelmaniac
Surface mount soldering geek
Global NLG Site Moderator
Sr.Tech NLG Member 1000+ Post
*

Total Karma Storms: 568
Offline Offline

Gender: Male
Posts: 2127


Few things are better than fixing an old game...


WWW
« Reply #4 on: September 15, 2008, 08:29:46 PM »

Model: C64/VIC-20
Symptom: Missing keys when typing

Commonly this is caused by dirty switches on the keyboard. If it is a single key or multiple keys that aren't in a pattern, then press them repeatedly for a few minutes to let the self wiping contacts clean the switch. If the keys are in a row or column then replace a defective 6526 CIA chip on the C64 or a 6522 VIA chip on the VIC-20.
Logged

I have too many hobbies! Electronics, gunsmithing, Miatas, arcade games, metal detecting, etc...

http://www.arcadecomponents.com
channelmaniac
Surface mount soldering geek
Global NLG Site Moderator
Sr.Tech NLG Member 1000+ Post
*

Total Karma Storms: 568
Offline Offline

Gender: Male
Posts: 2127


Few things are better than fixing an old game...


WWW
« Reply #5 on: September 15, 2008, 08:30:05 PM »

Model: C64
Symptom: Will not read/write to/from the serial port

Replaced a bad 6526 CIA IC and tested with diagnostics.
Logged

I have too many hobbies! Electronics, gunsmithing, Miatas, arcade games, metal detecting, etc...

http://www.arcadecomponents.com
channelmaniac
Surface mount soldering geek
Global NLG Site Moderator
Sr.Tech NLG Member 1000+ Post
*

Total Karma Storms: 568
Offline Offline

Gender: Male
Posts: 2127


Few things are better than fixing an old game...


WWW
« Reply #6 on: September 15, 2008, 08:30:29 PM »

Model: C64
Symptom: Missing audio channels, stuck sounds, or no audio

Replace the defective 6581 SID chip. In rare cases of no audio at all it may be the 906114-01 PLA IC. (It is a custom programmed 82S100 chip)
Logged

I have too many hobbies! Electronics, gunsmithing, Miatas, arcade games, metal detecting, etc...

http://www.arcadecomponents.com
channelmaniac
Surface mount soldering geek
Global NLG Site Moderator
Sr.Tech NLG Member 1000+ Post
*

Total Karma Storms: 568
Offline Offline

Gender: Male
Posts: 2127


Few things are better than fixing an old game...


WWW
« Reply #7 on: September 15, 2008, 08:30:49 PM »

Model: VIC-20
Symptom: No audio, missing sounds, or stuck audio

Replace the 6560 VIC IC. This IC does both audio and video functions.
Logged

I have too many hobbies! Electronics, gunsmithing, Miatas, arcade games, metal detecting, etc...

http://www.arcadecomponents.com
channelmaniac
Surface mount soldering geek
Global NLG Site Moderator
Sr.Tech NLG Member 1000+ Post
*

Total Karma Storms: 568
Offline Offline

Gender: Male
Posts: 2127


Few things are better than fixing an old game...


WWW
« Reply #8 on: September 15, 2008, 08:31:08 PM »

Model: C64
Symptom: Multiple RAM errors

If a machine has more than 1 bad RAM chip (4164) or comes back for another repair of yet another defective RAM chip then replace the external power supply. They are known for deteriorating and blowing RAM chips on the computer. They are potted and not repairable. Luckily they can be easily found.
Logged

I have too many hobbies! Electronics, gunsmithing, Miatas, arcade games, metal detecting, etc...

http://www.arcadecomponents.com
channelmaniac
Surface mount soldering geek
Global NLG Site Moderator
Sr.Tech NLG Member 1000+ Post
*

Total Karma Storms: 568
Offline Offline

Gender: Male
Posts: 2127


Few things are better than fixing an old game...


WWW
« Reply #9 on: March 05, 2009, 09:57:14 PM »

Model: SX-64
Symptoms: Dead. Drive light stuck on.

This one was a bugger. It had liquid spill damage.

Replaced the corroded cartridge slot, 2 40 pin sockets, 1 24-pin socket, and 2 28-pin sockets. Cleaned the pins on the VIC-II chip. Replaced a bad CPU, PLA, SID (would work, but had no white noise channel), 74LS08, 74LS06, 74LS139, 74LS258, 2x 74LS257, and 8 DRAMs (2 were bad, but went ahead and replaced them all.)

Replaced a bad 901229-05 ROM on the disk controller board to fix the drive light issue.
Logged

I have too many hobbies! Electronics, gunsmithing, Miatas, arcade games, metal detecting, etc...

http://www.arcadecomponents.com
channelmaniac
Surface mount soldering geek
Global NLG Site Moderator
Sr.Tech NLG Member 1000+ Post
*

Total Karma Storms: 568
Offline Offline

Gender: Male
Posts: 2127


Few things are better than fixing an old game...


WWW
« Reply #10 on: March 09, 2009, 09:28:45 PM »

Model: 64
Symptom: Dead. Garbage on screen.

The board was sent with symptoms described as "Blank blue screen."

When put on the bench it would throw garbage on the screen - a lot of @ symbols and some were flickering. The well calibrated finger found one of the DRAM chips was shorted and getting hot.

Socketed and Replaced the DRAM chip then got the reported blank blue screen. Tried a diagnostic cart to see if it would “play blind” but it wouldn’t. This ruled out a character ROM issue.

Tried a Music Composer cartridge and it tried to start it but couldn’t. The screen went garbled on graphics mode. This pointed to a PLA chip problem. Socketed and replaced the PLA then ran diagnostic loops on the board.

Informed the customer that frying DRAM chips is a pointer that the power supply may be dying.
Logged

I have too many hobbies! Electronics, gunsmithing, Miatas, arcade games, metal detecting, etc...

http://www.arcadecomponents.com
channelmaniac
Surface mount soldering geek
Global NLG Site Moderator
Sr.Tech NLG Member 1000+ Post
*

Total Karma Storms: 568
Offline Offline

Gender: Male
Posts: 2127


Few things are better than fixing an old game...


WWW
« Reply #11 on: August 23, 2009, 10:53:28 PM »

Model: C64
Symptom: Dead, black screen

Replaced a bad 901225-01 ROM. Board failed audio tests. Replaced bad SID and ran diagnostics in a loop to burn in unit.
Logged

I have too many hobbies! Electronics, gunsmithing, Miatas, arcade games, metal detecting, etc...

http://www.arcadecomponents.com
channelmaniac
Surface mount soldering geek
Global NLG Site Moderator
Sr.Tech NLG Member 1000+ Post
*

Total Karma Storms: 568
Offline Offline

Gender: Male
Posts: 2127


Few things are better than fixing an old game...


WWW
« Reply #12 on: August 23, 2009, 10:53:53 PM »

Model: C64
Symptom: Dead, Black screen

Replaced bad PLA chip and ran extended diagnostic loops to burn the unit in.
Logged

I have too many hobbies! Electronics, gunsmithing, Miatas, arcade games, metal detecting, etc...

http://www.arcadecomponents.com
channelmaniac
Surface mount soldering geek
Global NLG Site Moderator
Sr.Tech NLG Member 1000+ Post
*

Total Karma Storms: 568
Offline Offline

Gender: Male
Posts: 2127


Few things are better than fixing an old game...


WWW
« Reply #13 on: August 23, 2009, 10:54:38 PM »

Model: C64C
Symptom: Reports incorrect RAM count

When running diagnostics the RAM errors are random and sometimes showing Address Bus errors.

Replaced 2 4464 DRAM. No change. Replaced the 251715-01 custom IC to repair board. Ran extended diagnostic loops to burn in board.
Logged

I have too many hobbies! Electronics, gunsmithing, Miatas, arcade games, metal detecting, etc...

http://www.arcadecomponents.com
channelmaniac
Surface mount soldering geek
Global NLG Site Moderator
Sr.Tech NLG Member 1000+ Post
*

Total Karma Storms: 568
Offline Offline

Gender: Male
Posts: 2127


Few things are better than fixing an old game...


WWW
« Reply #14 on: August 25, 2009, 06:26:16 AM »

Model: C64
Symptom: Totally blue screen on monitor

Background and foreground were all one solid blue color. Replaced the VIC-II (6567) chip and ran diagnostics in a loop to burn in unit.
Logged

I have too many hobbies! Electronics, gunsmithing, Miatas, arcade games, metal detecting, etc...

http://www.arcadecomponents.com
channelmaniac
Surface mount soldering geek
Global NLG Site Moderator
Sr.Tech NLG Member 1000+ Post
*

Total Karma Storms: 568
Offline Offline

Gender: Male
Posts: 2127


Few things are better than fixing an old game...


WWW
« Reply #15 on: March 15, 2013, 04:34:41 PM »

Model: C64
Symptom: "Bad RAM 7"

Removed and socketed the RAM chips. Replaced 1 bad RAM and tested.
Logged

I have too many hobbies! Electronics, gunsmithing, Miatas, arcade games, metal detecting, etc...

http://www.arcadecomponents.com
Pages: [1] Go Up Print 
« previous next »
Jump to:  


If you find this site helpful, Please Consider Making a small donation to help defray the cost of hosting and bandwidth.



Newlifegames.com    Newlifegames.net    Newlifegames.org
   New Life Games    NewLifeGames  NLG  We Bring new Life to old Games    1-888-NLG-SLOTS
Are all Copyright and Trademarks of New Life Games LLC 1992 - 2017


FAIR USE NOTICE:

This site contains copyrighted material the use of which has not always been specifically authorized by the copyright owner.
We make such material available in an effort to advance awareness and understanding of the issues involved.
We believe this constitutes a fair use of any such copyrighted material as provided for in section 107 of the US Copyright Law.
In accordance with Title 17 U.S.C. Section 107, the material on this site is distributed without profit to those
who have expressed a prior interest in receiving the included information for research and educational purposes.

For more information please visit: http://www.law.cornell.edu/uscode/17/107.shtml.

If you wish to use copyrighted material from this site for purposes of your own that go beyond fair use,
you must obtain permission directly from the copyright owner.

NewLifeGames.net Web-Site is optimized for use with Fire-Fox and a minimum screen resolution of 1280x768 pixels.


Powered by SMF 1.1.20 | SMF © 2013, Simple Machines
Loon Designed by Mystica
Updated by Runic Warrior
Page created in 0.159 seconds with 21 queries.