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That’s 15v not 25v doh.

I've run into a small snag I'm trying to work through. The 25v dc-dc converter got discontinued out from under me. (sigh) but that's probably solvable. If nothing else the manufacturer publishes the full parts list and schematic and there are a few still in stock. The arduino part for battery...

No vinegar syndrome on these so far. Just the weirdness with contrast. I have two others that seem to be missing random pixels in the middle. I’m not sure if it’s damage to the LCD itself or the polarizer. It kind of looks like something might have impacted/pressed against the display on those...

I have a couple of machines that exhibit this behavior and I'm trying to figure out if it's old and degrading components of if I just don't remember it. I've noticed that the LCDs seem to fade on one edge and become more solid on the other. It's pretty dramatic when the display is showing solid...

Progress!! https://forum.vcfed.org/index.php?threads/tandy-1400-any-varients-with-hdd-expansion-slots-please-help.35455/post-1418041 Second iteration of the board actually works, mostly :) There's something off in the charging subsystem that causes the TP5100 modules to let out the magic smoke...

Well, the most recent iteration mostly works: It will power the machine off the original 12v power brick, or a 2s Li-ion pack. There's something wrong with how I have the charging circuit setup though, it popped the TP5100 module when I plugged in the charger with the machine powered on. The...

It has the board, but not really the connector unfortunately. At least not the parts I was looking for to try to identify it. Good video though!

@acadiel any chance you can get some better shots of the connector from different angles? The 1100FD mother board doesn't have it installed and I'm attempting to identify what that connector is.

Got the profile of the board right, but screwed up the -22v boost converter ... I'm going to have to rework that circuit on a prototype board to figure out the right way to put it together .. With the bodges in place, it blows the fuse on start up.. Thankfully, it doesn't seem to hurt the 15v...

Nice! I've been toying with the idea of a replacement board, this would be insanely helpful to have!

I've been playing around in another thread with the idea of building a replacement PSU board for the 1400FD/HD. Anyone with an actual EE willing to take a look at this nightmare? I haven't ordered boards yet and have not built this circuit .. https://github.com/arlaneenalra/Tandy1400/tree/main...

https://www.digikey.com/en/products/detail/mean-well-usa-inc/N7812-1PV/22119034 ... hmm I can use this to get -12V .. but unless I want to push my input to 24v (which is higher than most of the stuff I'm working with can handle, I'm not going to get the +12v most of the stuff I'm seeing want's...

I think I'm going to do a mix of custom and pre-built. I saw those little modules but couldn't find them in all of the voltages I wanted. I've picked up a set of: https://www.digikey.com/en/products/detail/monolithic-power-systems-inc/MEZD72401A-G/6823842...

No wonder this hasn't been working the way I want it too! I've been trying to figure out what I was doing wrong for about a week now only for it to hit me that the visual arrangement of the pins in the circuit diagram on the calculator don't match the pin ordering on standard chip. Sigh, I...

That might actually be the answer I'm looking for. The whole thing overall draws about 27w (12v 2.2amp). So, using something like https://www.monolithicpower.com/en/mezd41502a-c.html to get a normalized 15v then building a couple of custom modules for the -22v and maybe -12v while using...

Unfortunately, I need around an amp on the 5v rail (could be a little more, I haven't fully measured it though so it could be a little more. What I'm replacing runs everything on a 2.25A 12V supply and the produces a 5, +/-12, and -22 rail off of that. The -22v rail has almost no draw, the 12V...

@Bentendo64 The PTH08080 looks promising for the 5v rail .. and that AZ34063UMTR-G1 ic looks promising for others. I was kind of hoping I could avoid laying out a bunch of voltage rails, but that may be the way I need to go :( Or designing a couple of reusable modules .. There's certainly enough...

I'm looking for a reliable source/brand/model of DC/DC Buck and Boost (or Buck/Boost) modules that are likely to have a consistent pinout/foot print and there are just way too many things to try. There are number of modules over on Amazon that I could use (like...

I have four main boards one I bought as a bare board and three other I picked up in supposedly dead machines. So far, I've found a couple of the large caps on the main board leaked and power supplies that were almost trashed from leaking caps. The contrast and volume pots are also touchy. Other...

Well, I was able to get a 1400HD board that to start up and power the display with this monstrosity and this pinout Pins 1 (white), 2 (dark blue), 3 (brown) , 4 (Grey), and 5 (Light Blue) all appear to be some kind of single lines. The machine will come up without them but give you a low...