Apple IIgs ROM 03 system bad error

[Verault]

I have two ROM 03 Apple IIgs systems that give intermittent errors "SYSTEM BAD 06010000" From what I looked up it seems to be an issue with the built in SERIAL IC on the main board.
Is that correct or is the issue something else? My concerns are system stability. IF I disable the modem port in the control panel and add a super serial card will the system work as intended sans the on-board serial components? Would that create a functioning machine? Two ROM 03 machines thrown away would be a huge waste, I am trying to get some use out of them. I guess they had inherent issues with the serial chips.

Would appreciate the feedback

 

[cruff]

Have you checked for leaking capacitors or bad solder joints for the serial chip? Maybe the issue can be resolved with a simple fix. Also, have you downloaded the IIgs Diagnostic disk images? I have three versions, one of the version 3 variants might tell you something more.

 

[Verault]

All caps were replaced and are fine. Yes i have diagnostics but they don't tell me anything. Like i said its intermittent. Sometimes its fine. Other times the serial connection flakes out and i can flag that error. Weird thing is is two different systems which leda me to think its not all that uncommon.

 

[cruff]

Unfortunately it looks like it might be hard to find those chips. Mouser has the 40 pin version listed in stock, but not the 44 pin version you'd need.

 

[Verault]

Is there anyway to completely disable the serial card portion of the mainboard and just install a standard Super Serial card II? Both machines work completely fine otherwise and it would be a complete waste if they didnt get use. I figure I could install the super serial cards for adt transfers and keep them going.

 

[cruff]

Seems to me like you should be able to disable the on-board serial ports and use a card, the ROM slot configuration menus should work for that. Unfortunately I don't have a serial card to try in my ROM 01 IIgs.

 

[Verault]

Well I realize I can change slot assignments in the control panel. But even if I change the modem/serial to "mycard" the diagnostics can still run and FAIL which makes the machine look as if its not working.

Its really a shame, I know how sought after Rom 03 boxes are. Both of these were bought from a school system. I used them with ADT for about a year and then they started showing symptoms.

 

[cruff]

Is it just the diagnostic disk, or a mini diagnostic built into the ROM or a report from GS/OS? Is it possible to just ignore the error report, or does it get in the way of running programs?

 

[Verault]

on Both units it is the Mini Diags built in. Can I ignore the error? I suppose but I will never feel good about the unit again, Id rather find a way and resolve/repair it if possible.

 

[cruff]

According to a ROM source listing found at https://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Computers/Apple%20II/Apple%20IIGS/Documentation/, the serial I/O chip test failure code 01 indicates a problem with the SCC register R/W test, which is testing some of the channel A and channel B registers. It tests registers 2, 12, 13, and some of the bits in register 15. Unfortunately it doesn't indicate which of the registers may have failed the test. The test appears to test all of the bit combinations in the registers. I'll have to experiment if the diagnostic disk images provide any more detailed tests for the SCC.

 

[Verault]

Thank you Cruff keep me informed. To be honest, even If I had access to the SMD 44pin IC being sold today, I dont have a hot air re-work station. And I have tried to replace this IC on a ROM 01 board in the past and damaged 5 traces. IF I could disable it and use an SCC card Id be happier. I can rework through-hole components all day long, but SMD is not my forte.

 

[cruff]

Can you see if there is a 3.58 MHz clock signal at pin 23 of the 8530 chip? Maybe there is a bad solder joint there.

That clock signal is output by the Mega2 chip, and if it did not make it to the 8530 SCC, the register writes and reads wouldn't function correctly. If the Mega2 chip wasn't outputting the 3.58 MHz clock, then the entire IIgs might not work correctly.

 

[cruff]

I had a further thought about this issue. Do you have a logic analyzer available? Even a small USB based one with 12 or 13 lines would work. We might be able to figure out if you have some bad solder joints at the SCC.

 

[Verault]

Sorry I do not. Multi meter and logic probe only.

 

[Lee Adamson]

I think those Zilog rs422 chips were used in a lot of other machines.  You ought not have tremendous trouble finding donors, I wouldn't think?

I have a ROM3 board that took a Maxcell Bomb to the face that I've been trying to fix, even though it is pretty hopeless (seriously man, it is *bad*, really capital-B *Baaaad*), just to see if I can.  If/when I get frustrated and give up, I'd be willing to trade that board to you for something interesting/useful, if you want it.  It would be easier to get the chips off with a hot air station, but if this donor board ends up being junk anyway then I guess it doesn't really matter if you pull up a bunch of pads trying to get them off, as long as none of the pins break.

Alternately, I could probably desolder the serial chips and send them to you, if/when I give up on trying to fix the board, although it makes me sad to scrap such things myself......... <_<

Likewise, if you want to get rid of one (or both) of your malfunctioning boards, maybe I could put myself together one working board to put in my spare case.  I'm more of a trader than a cash buyer, though......