exxos's Atari, Amiga & retro forum

exxos wrote: 09 Feb 2022 19:40 Not seen one of those testers before.. Assume its OK.. Checking the datasheet will give a idea if the gain is OK.

Yup, can't really find anything, the part is marked C202IR K

EDIT - scrub that, dodgy eyes, it's C2021R K - closest I can find datasheet wise is this, but tbh I don't know what this is telling me: https://pdf1.alldatasheet.com/datasheet ... C2021.html

Looks like about 280hfe but your meter says different. :shrug:

I think I need to refresh on theory tbh.

Anyhow I snagged a replacement IC for £1.50 so will swap that out when it arrives.

BennehBoy wrote: 09 Feb 2022 21:43 I think I need to refresh on theory tbh.

Anyhow I snagged a replacement IC for £1.50 so will swap that out when it arrives.

Be interesting to see what that tests say.

The HFE I got from this chart.. Your meter says 6mA, but the graph is pretty constant anyway.


EDIT:

Still in spect anyway I guess..

Sorry I meant I've found a replacement for the motor driver IC, the HA13431.

The reason I'm suspicious of it is that the motor should be running when pin 2 is low, and it's not (the motor windings all have continuity). Assuming I interpreted the datasheet correctly.

I think that transistor is inverting the signal coming from the VIA chip on the drive electronics, that signal is high for on low for off. Given that the transistor is functional (if not measuring the expected gain), it should still act as an inverter - I just need to check the circuitry around it to see if I'm right. I'll check that pin 2 to see if it's shorted to ground later.

BennehBoy wrote: 09 Feb 2022 19:23 PXL_20220209_192039717.jpg


I'm no expert on transistors but I think this is ok?

I have one of these testers, handy little buggers.

rubber_jonnie wrote: 10 Feb 2022 00:10

BennehBoy wrote: 09 Feb 2022 19:23 PXL_20220209_192039717.jpg

I have one of these testers, handy little buggers.

So did I, until I failed to observe the "please discharge before testing" warning. :cry:

C128 is due today according to ParcelForce!

I managed to find a working 1571 disk drive from a reputable seller in the Netherlands, that should rock up next week.

derkom wrote: 10 Feb 2022 07:28

rubber_jonnie wrote: 10 Feb 2022 00:10

I have one of these testers, handy little buggers.

So did I, until I failed to observe the "please discharge before testing" warning. :cry:

Oh No!!!

BennehBoy wrote: 10 Feb 2022 08:29 C128 is due today according to ParcelForce!

I managed to find a working 1571 disk drive from a reputable seller in the Netherlands, that should rock up next week.

Cool. Would like a C128, unusual machine, but prices are high.