PEB troubleshooting

[bradleyb]

I just picked up a TI and PEB. While the console appears to work great, I haven't been able to get any of the expansion boards to work.

The PEB includes:

Flex cable interface

32x8 memory expansion

RS232 interface

Disk controller, with dual floppy drives (QUME 142)

 

When powering the PEB on, both floppies' spindles turn for a few seconds. Trying to access either floppy drive as described in the manual results in a brief flash of the disk controller's LED, but no activity on the floppy light, and a disk error 00.

 

Using the SIZE command only results in 13928 bytes free.

 

I imagine there is an easy way to do a loop-back test on the serial port, I just haven't found any instructions yet.

 

I'm wondering if these are common symptoms for a PEB that's been out of commission for a while, and what I should try next?

 

Thanks!

 

[Opry99er]

Could be any number of things. Make sure your flex cable is seated firmly and strongly in the side port of the TI. I would take all the cards out of the PBox and clean the contacts, then reseat them all firmly. Make sure your PBox is turned on first, then the console. With XB in the cart slot, try SIZE again, then report back.

[+Ksarul]

Ack, the dreaded Qumetrak 142 drives. Each of those drives pulls as much current as the original full-height drive that came with the PEB, and two of them will draw too much power. Unplug one of the drives and try to see if the cards start working. . .of, and as those are the 142 variant, they are single-sided drives. The 242 is a double sided drive. Double check the giant belt inside each of the drives as well, it may be slipping or even broken, which will cause other disk problems.

[Shift838]

Also, not sure how familiar you are with the TI, but make sure the Flex Cable Firehouse connector that plugs into the 99/4a side port has the foot down resting on the table and not toward the ceiling. It will plug in either way and I have seen people make this mistake.

 

If you have a speech synthesizer you can hook that up and if you have Extended Basic you can do a CALL SAY("HELLO") To make sure the port is working.

 

For any of the cards to work you have to have the IO working between the 99/4a and the PEB via the flex cable card.

[bradleyb]

I disassembled the whole PEB and cleaned it out, it had been stored in the original foam-lined cardboard box from TI, and there was little bits of foam everywhere. After reassembly, SIZE reported the expanded memory!

Still getting error 00 on the drives though. I was just going to ask about about the power requirement, because the 12V on one of them is powered by an external AC supply and rectifier board inside the case. I have the original documentation for the QUME kit and it describes setting it up and everything. The belts both look ok. The heads move freely as well.

 

I used to be familiar, I had one as a kid Never had a PEB or any drives though.

Edited February 8, 2018 by bradleyb

[Opry99er]

Have you tried:

 

OLD DSK1.TEST (all caps, mind you) from XB? If the light comes on, that's one thing... if nothing happens, and you get an immediate error, that is another.

[+Ksarul]

OK, if one of the Qume drives is externally powered, that potential problem is resolved. Good that the belts are still good too. Do you have a Disk Manager cartridge? If so, try and use it to catalog a disk. You'll probably get the same error you did before with your other tests, but this will just validate that. Make sure the disks are inserted properly too (I seem to remember there was something diffierent about the orientation of the Qume drives, but that was when I had a pair of them more than 30 years ago, and I didn't keep them long enough to note it for permanent use).

[bradleyb]

OLD DSK1.TEST, results in no light on the drive, very brief flash on the controller, and an immediate I/O error 00

[bradleyb]

I unplugged and opened up my disk controller card, and noticed that the voltage regulators were still warm. On a hunch I checked the voltage on the PEB's bus, which I believe are supposed to be around +/-16V and +8V, and I found them to be more like +/-23V and +13V. Is that way too high or not a problem?

[bradleyb]

Well it turns out that my disk controller (PHP1240) is bad. I swapped in another one and the floppy fired right up!

 

I'd like to figure out what's wrong with the first card though. maybe I can find the fault easier since I have a good one to compare with.

The PEB voltages are still too high though, so I won't be doing much with it until I can fix that. I'm going to start by replacing all the electrolytics.

[Opry99er]

Awesome!!! A bad card, eh?

 

Yes, lets dig in and figure it out.

[Tursi]

Error 00 means that the name "DSK1" was not found on any of the DSR ROMs. Making sure first that you typed it in uppercase, it seems like the card at least partially works (because the LED lit up during the search), but the console apparently couldn't read the ROM.

 

We could start doing some diagnostics if you have a MiniMemory, maybe? (It's just an easy way to poke at the hardware...)

[bradleyb]

I don't have Mini Memory, no. I'm still trying to figure out the darn PEB voltage problem. I replaced the capacitors, but there was no change.

 

I saw this at Thierry Nouspikel's page: "All voltages will be lower if cards are still present inside the box (approx +8, -16, +16V) than in a bare PE-box (+13, -25, +25V). This is normal."

But I'm seeing those high voltages even with all the cards installed.

[+arcadeshopper]

likely if your are overvolting the voltage regulators one or both has given up the ghost. A quick shotgun fix would be to replace them and these run a lot cooler too https://www.arcadeshopper.com/wp/?page_id=11#!/PEB-Voltage-Regulator-upgrade-replacement-kit/p/78680120/category=16275021