Jan Beta | TRS-80 Model 1 Level II Inspection & Power Supply Build @JanBeta | Uploaded September 2020 | Updated October 2024, 1 hour ago.
I 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! - pcbway.com

This video is part of the #SepTandy 2020 festivites. Other participants are:
Mr Lurch's Things: youtube.com/mrlurchsthings
Josh Malone: youtube.com/channel/UCjU4lK6YTMKnMj7-XgTsv9w
The Retro Channel: youtube.com/TheRetroChannel
Adrian's Digital Basement: youtube.com/AdriansDigitalBasement
DaveJustDave: youtube.com/mrdavejustdave
MindFlareRetro: youtube.com/MindFlareRetro
Tech Tangents: youtube.com/AkBKukU
Retro Spector: youtube.com/c/RetroSpector78
LGR: 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: 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: 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: github.com/calphool/TRS80MXS/blob/master/img/powersupply.pdf

Here's Mr Lurch building one of the aforementioned power supplies: 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: 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: classiccmp.org/cpmarchives/trs80/mirrors/kjsl/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