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NavigationGeneral Archive Searches Converting TRS-80 Media Emulation/Conversion The TRS-80 Models
TRS-80 Revived Site by Ira Goldklang's is an archive of everything related to the Tandy Radio Shack TRS-80 microcomputer lines. Site contains emulators, programs, manuals, books, patches, games, hints, discussions, questions, forums, and tons more.
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Not a solution but perhaps some insight:
http://newsgroups.derkeiler.com/Archive/Comp/comp.os.cpm/2005-07/msg00316.html
Bad electrolytic caps – ?
Assumed this advice was already checked:
– http://www.trs-80.com/trs80-zaps-hardware.htm#m4pwrsup
– http://www.trs-80.com/trs80-zaps-hardware.htm#mod4power
More comments about repairing p.s. below. Warnings almost go without mention, but should be mentioned: PROPERLY DISCHARGE THE CAPS BEFORE YOU MESS WITH THEM. THEY CAN PUT YOU IN THE HOSPITAL. IF YOU ARE UNCOMFORTABLE DO NOT OPEN THE COMPUTER — IT IS DANGEROUS. If you don’t know what you’re doing, get educated first or don’t go there! You have been warned! Caps will hold their charge even if the machine has been off… sometimes for years.
– http://www.vintage-computer.com/vcforum/archive/index.php/t-20521.html
“…some TRS-80 Model 3 and 4 computers off of Craigslist that I am trying to repair. They have the same Metalized paper Capacitors as leaknoil describes above that are damaged. I did some research on the web trying to find info on what is the desired replacement for them since they are no longer made except in higher voltage ratings. Apparently this is a high failure rate component(obviously, since so many members have had the same problem). What I found is that Metalized Plastic Capacitors are what people are using now. That includes Metalized polypropylene, polyester or polystyrene. They are much more reliable than the old paper ones and will work fine. When ordering you have to make sure you get ones with voltage ratings equal to or greater than the one you are replacing. Be sure you are looking at the A/C voltage ratings. The same capacitor that has voltage rating of 450V DC may only have an A/C rating of 250V. Some listings only give the D/C rating.
Most electronic distributors like Mouser and Digikey carry these parts.”
getting closer…
http://groups.google.com/group/comp.sys.tandy/browse_thread/thread/54a7342863ced0fc/934129be6e7fa513?q=astec+power+supply+trs-80#934129be6e7fa513
“The Model 4′s ( 4, 4P, 4D ) originally came with 3 different power supplies from Radio Shack.
#1 The Tandy version
Radio Shack # 1700218
on PC Board 8709365 Rev. C
was 120VAC only.
#2 Astec Power Supply
Radio Shack part # 8790021
Astec part # AA 11320
was 120VAC only.
#3 Astec Power Supply
Radio Shack part # 8790043
Astec part # AA 12090
had a slide switch, SW1, to support
both 115V and 230V.
Model 3 only used 1 version that was not switchable.
This info is from Howard W. Sams & Co. Inc. Computerfacts CSCS13. – Don Inglehart “
FYI Emerson Network Power owns what was Astec now. I received this mostly useless message back today.
—–
“As the AA11320 is proprietary to OEM this power supply was
used for. We do not have a replacement to recommend from our present
standard product line. I apologize for the inconvenience.
If you have further inquiries, feel free to contact us again or visit
our website at http://www.powerconversion.com.
Best regards,
Warren M. Gonzales | Technical Support Engineer | Embedded Power
Emerson Network Power
T +1 888.412.7832 (North America) | 0 800.032.1546 (U.K.)
TechSupport.EmbeddedPower@emerson.com