Recent content by spiderx

There's a switch for the battery and some jumpers you can set which will set for 'overcharge' but it shouldn't draw much power. There's a thermistor which controls how often the dram refreshes, that might be damaged which would make it constantly refresh the ram.

I just hate those round pin sockets, but that's pretty cool.

I would not recommend it, the builtin charger probably won't be able to charge it if it's that low. You can try to charge it with a dc power supply (like a bench power supply) set to a certain current and voltage limits. That said, if you do get it up to the proper voltage without it exploding...

That said about the charger, you can leave the charger connected always, and it will suffer very little battery degradation. They tested for 6 months and found it was minimal. There's documentation about it in the repair manual.

The test points are circled in dotted line fashion, look for "VP" next to the letter "D" after the word "MOSU BOARD" and +5V in the lower left corner of the MOSU board. There are many test points that you can use for troubleshooting. Also GND(P) near the cutout for the battery pack on the left...

Already got one.

Jeff, actually, I think I can just use a DB25 gender changer since I have the #706 and #715 cables for the HX-20. I appreciate the work you both do, and I wasn't complaining. Just trying to collect the best info for making serial connections to the HX-20 here. I could also use a DB9-DB25 but...

Not for the HX-20, but at least he does state "For the HX-20 you will need an 8-pin DIN to 8-pin Mini DIN cable." However no such cable exists, you have to make that yourself.

Thanks Jeff, I've watched your video, I'll have to rig up a cable and give the DRAM test rom a try.

I did look up those suppository testers, apparently they heat up a suppository to a certain temperature and record how long it takes to dissolve. So, if it takes too long, or maybe too short, it would fail the test. I imagine there's a temperature measurement, some detector for the fluid that is...

I tried it, but it didn't charge it right - need to change out the resistor for charging -- the big 2w green one, and then you also have the timing wrong, but it's said that you can leave the battery connected for at least two months to the charger without any battery degradation (check the...

A lot of the higher priced listings nobody ever buys, they just keep listing them. I think they do that to set a price reference so when you see that one for $100 less you're like 'wow thats a great deal!', but you can check the completed sold ones to get an idea what the going rate is, and look...

I did get one, but it looks like it takes a mini din not a din, so back to square one. I might be able to wire one up with those breadboard jumper cables, at least temporarily.

Where did you test that? VRF is voltage reference for the 7508 cpu and it's just a sampling, if it's below 1.8 then it's "critical low voltage" and you get a warning. Otherwise, it should be between 1.8 and 2.x on that VRF test point. That's the input for the ADC and you can adjust that with the...

The screen should get about 20v with +15 and -5, making the 20v difference. The overvoltage protection kicks in around 7.5v so I'm sure that the power supply voltage wouldn't be causing an issue. I was seeing 6.75v from my power supply when it's connected under load and same as you about 9v...