30-11-2025, 12:10 AM
(22-09-2020, 07:18 PM)ChickenMan Wrote: This is the small audio amp I installed on the right hand side of the System 80 to the right of the Cassette player and in front of the power supply where there is a ton of room. I had to drill a small 1/4" hole in the case so the volume control pot can come through.
Since most of the TRS-80 games send the sound out via the external cassette port, unfortunately the System 80 has the main cassette built in, so no sound out the back cassette port 2 without some sort of modification. I made no modification and just picked up the sound signal thats going to the inbuilt cassette unit from Point 1 in the pic. Picked up 5v from Point 2 and earth from Point 3. A 50mm 4ohm speaker is mounted under the Video motherboard in the spot already provided for it. That spot though is designed for a 60mm speaker, so had to put in a holding strap to keep it in place.
The small 3w audio amp (uses PAM8403 chip ) with knob was bought off ebay $9.90, the speaker $10 and some wire so not an expensive upgrade.
This is great. I am lucky enough to have acquired a Video Genie here in the UK and really like the machine. I am only (very) amateur at soldering but this looks within my modest skillset. I have all the parts for this but could you help me identify the resistor in the photograph? Would be great to get some sound out of this computer. Thanks.