TRS-80 Model 1 Level II Inspection & Power Supply Build
1,061I got my hands on a TRS-80 Model 1 (Level II)! I'm inspecting the machine and building a DIY power supply and a video cable for it in this episode. // Kindly sponsored by PCBWay - Get your first PCBs free! - https://www.pcbway.com/
This video is part of the #SepTandy 2020 festivites. Other participants are:
Mr Lurch's Things: https://www.youtube.com/mrlurchsthings
Josh Malone: https://www.youtube.com/channel/UCjU4lK6YTMKnMj7-XgTsv9w
The Retro Channel: https://www.youtube.com/TheRetroChannel
Adrian's Digital Basement: https://www.youtube.com/AdriansDigitalBasement
DaveJustDave: https://youtube.com/mrdavejustdave
MindFlareRetro: https://www.youtube.com/MindFlareRetro
Tech Tangents: https://www.youtube.com/AkBKukU
Retro Spector: https://www.youtube.com/c/RetroSpector78
LGR: https://www.youtube.com/LazyGameReviews
I highly recommend checking these people out if you haven't done so already!
Here's a playlist of all SepTandy 2020 videos that is regularly updated: https://www.youtube.com/playlist?list=PLxbeEn-s3xXCVnEwkqSUOxyKZnsBEdv1r
The excellent TRS-80 technical manual is available for download here: http://www.1000bit.it/support/manuali/trs/TRS-80%20Technical%20Manual%20%281978%29%28Radio%20Shack%29%28pdf%29.pdf
My PSU design is based on Dean Bear's much more powerful design: http://www.trs-80.com/wordpress/zaps-patches-pokes-tips/zaps-model-i-power-supply/
The schematic I based things on is available as a pdf here: https://github.com/calphool/TRS80MXS/blob/master/img/powersupply.pdf
Here's Mr Lurch building one of the aforementioned power supplies: https://www.youtube.com/watch?v=PLJCZDwDxfk
Here's what I used for my build:
I used a 15V (2x7.5V) 10VA center tapped transformer for the AC side and a 12V (2x6V) 18VA center tapped transformer for the DC supply. Mostly because I had these parts laying around anyway. The AC side is a bit overpowered (it should only need 350mA), while the AC side should be just enough (needs around 1A).
- 160 x 100 mm Perfboard (preferrably single sided)
- BOPLA KS 450 Universal Case 188 x 110 x 70 mm
- Bridge Rectifier (I used a KBPC604)
- 1000uF 35V Capacitor
- 1k Ohm resistor
- LED
- 4 wire electrical wire
- Power switch (on/off)
- Fuse holder
- I used a 1A slow fuse, but a 500mA fuse should be enough for a 230V supply
Hirschmann MAS 50 5-Pin DIN plugs*:
DE: https://amzn.to/3gWrMZM
For the video cable you just need a coaxial cable, an RCA plug and another 5-pin DIN plug. The pinout is here: http://www.classiccmp.org/cpmarchives/trs80/mirrors/kjsl/www.kjsl.com/trs80/mod1intern.html
This video was sponsored by PCBWay.
TIME STAMPS:
0:00 Introduction
1:26 Sponsor Message
1:50 Inspecting the TRS-80
10:24 Building a Power Supply
20:19 Modding the Case
26:24 PSU Unconnected Test Run
27:45 Making the Power Cable
36:44 Making a TRS-80 Video Cable
38:22 TRS-80 Test Run
44:49 Conclusion
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#JanBeta #Powersupply