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Thanks for the photo! It is indeed a Model 1 power supply. If the DC voltage is indeed around 10v, then my guess is that one of the diodes inside died. You should be able to drill out those rivets and take the bottom cover off to get access to the two diodes inside.

The DC voltage is used to generate the 12v DC. So if you're getting 9.9v DC, the TRS won't be able to convert that to 12v DC. Can you double-check your pins with the ones listed here? Can you also please post a photo of the bottom of your power supply?

It's the original image from an ad. In 1981, Radio Shack ran some ads in popular Japanese microcomputer magazines. I got the image from one of those ads. Examples are here and here. I think that maybe the Japanese TRS-80 was initially released with TRSDOS 2.2, as I see it mentioned here in a...

Here you go: https://www.shockrisk.com/index.php/2024/05/01/trsdos-v2-3-for-japanese-trs-80-model-1/

I was able dump my floppy disk, and it did contain the Japanese TRSDOS! I've posted it here: https://www.shockrisk.com/index.php/2024/05/01/trsdos-v2-3-for-japanese-trs-80-model-1/

One more update. I noticed that the version of the FreHD loader I used was older. I found the newer version, and it looks good! I think the challenge now will be to get a DOS image that can boot on the Japanese TRS-80.

Thank you! Rookie mistake on my part. It was really late last night, but I wanted to see if I could make any progress. HUGE PROGRESS TODAY!! I tried the script that displays the contents of the SD card, and it worked!! 10 OUT 236,16 20 OUT 195,2:OUT 196,8:GOSUB 100 30 OUT 194,ASC("/"):OUT...

More progress! I found a 4gb SD card and got a bit further. I re-ran the following: 10 OUT 197,1:FOR I=0 TO 64:PRINT INP(196);:NEXT Output looks good, as per George, I should see "254 254 1..." When I try to run the command to boot up the FreHD, the system still locks up. 10 POKE 16912,56:OUT...

Volume already named FREHD. The cable is pretty short already, picture below. I made my adapter based on Bill Buzbee and Larry Fosdick's instructions found here. I triple-checked all the traces, and they seem to be asking per instructions (note the connector is upside down because I incorrectly...

Thanks for checking, mine is the same, at 2.56v. This confirmed nothing funky was going on the power rails, so I continued with additional troubleshooting, and I've made some progress! I was running the FreHD 5v from the TRS-80, but the TRS-80 hard drive manual says that the HD must be turned...

Thank you for the info Kool65, extremely helpful! On my first try I did get one green blink because the system wouldn't boot, but then I started troubleshooting and I accidentally replaced the GAL with a non-programmed one, and I also tried a second FreHD I assembled (the one in the above...

I've build a FreHD and trying to connect it to my TRS-80 Model 1, but it's not working. Can someone with a working FreHD help? I'm made both, the FreHD and the Model 1 adapter. If you connect your FreHD to a power 5v power supply with the SD card inserted but without connecting the FreHD to...

This! I thought the Japanese TRS-80 just had a different character set, but the ROM and its mapping is different so that regular DOS systems won't boot. There's no archived copy of a Japanese DOS disk. My system did come with a disk drive and a floppy inside, I'll try to dump it to see if...

A couple of minor updates. I used a friend's greaseweazle to read back the contents of a floppy disk written using my IE w/ the bootstrap program and verified that the disk reads back and all the content was written correctly. This narrows the issue down to the IE for the most part. Jürgen...

This seems to be happening. I noticed that on system boot, the interrupt doesn't start occurring every 25ms until the floppy disk is finished reading. Once the disk is finished loading and the system is stuck, the interrupt continues occurring every 25ms. Thanks for the suggestion, I messaged...

Noted, on my to do list 📝 Yes, but I wouldn't think this has anything to do with the issue, as it just has a different character set. Shouldn't cause 4 different types of DOS's to fail to load. Loads no issue... Don't have a spare IE or disk drive unfortunately. I'm in Japan so hard to come...

I checked the interrupt on the IE and traced it through. IE generates it correctly, its clock rate is at 40hz (once every 25ms, or 40 times per second). Yes and Yes, both are at 5.0v and 12.0v Attaching photos of the IE and Disk Drive in case that helps. Note that on the disk drive, I've...

Overdue update on this. I got a battery-powered oscilloscope probe, and it confirms the large spike does not exist. The spiking was an artifact as suggested! Which is great!! Thanks all for your help!

I have a Japanese TRS-80 model 1 that I can't seem to boot from a floppy disk. I'm creating the floppy disks using a cassette input and Büssert's Bootstrap program. The creation of the disks seems to go through without errors. I've tried to write three different DOS programs on new disks...

Great point! Will try this. I'm traveling for next 3 weeks, I'll test this out once I get back. When I first got the units, the power switches showed like >50kΩ resistance when turned on. The switches don't come fully apart, but I managed to get it to <1Ω by spraying contact cleaner inside...