Dead BBQL from old Gold Card

[Chr$]

Don’t try that gold card until you have some other thoughts on it!

I have some other spare ZX8301's

It may have been completely unrelated, in fact very likely it was due to the multiple pulls/plugging in of the power plug and/or RGB cable.

[vanpeebles]

I'll stand in the corner with my face like this:

>_<

[Chr$]

No, the GC doesn't work in the BBQL, instead now it flickers the screen a bit and then makes an awful fuzzy noise from the QL speaker. Then I noticed that the backplane is not entirely standard. What I thought was some sort of regulator to provide extra power to the backplane is actually a TIP112 transistor. The wiring is a bit messy and I'm not sure where that goes yet.

I did however put all the old case modded QL contraption back together and to my utter shock, it booted and tells me it has a HDD card and Gold Card. So that appears to be ok. I cannot get further for now as I don't have an AT keyboard to attach to it (and the original k/b connectors are well hidden). Here is a pic:

Back to the original BBQL - it doesn't seem right since I changed the ZX8301. It seems to take longer to react to the F1/F2 keypress and sometimes I get weird large numbers at boot, like this:

The ZX8301 in the donor wasn't actually labelled as a ZX8301 and didn't have this 5-diode mod like the original:

Could that be the cause of my new BBQL woes?

[1024MAK]

Smells like a RAM fault to me. See this helpful web page and the online decoder/calculator is here.

Could also be a dry solder joint, a poor connection (e.g. on an IC socket), or maybe a track that has a crack in the copper conductor. With all the disturbance, that may explain why it’s got worse and why it was not always showing up.

Edit:

Minerva (Sinclair QL) Faulty Ram Decoder v0.2

- MINERVA OUTPUT SCREEN -
-------------------------
WRITE: F F F 9 C F F F
READ: 7 F 7 9 4 7 F F
ADDRESS: 0 0 0 2 0 0 5 4
-------------------------

ADDRESS < 30000
BINARY STRING: 10001000

IC8 (BAD)
IC7 (GOOD)
IC6 (GOOD)
IC5 (GOOD)
IC4 (BAD)
IC3 (GOOD)
IC2 (GOOD)
IC1 (GOOD)

The Original Program (ram3_ramfail.bas) was written for the SINCLAIR QL in SUPER BASIC language by Dominic Brown (1990).
Converted in PHP language by Xad/Nightfall (8/5/2015).

And don’t worry about the diodes mounted on top of the 8301. They have been added to help to protect it from voltage spikes on the RGB video output port.

Mark

[Chr$]

Oh that comes from Minerva does it, I see.

Since I swapped the ZX8301 for another it seems to be fine. I'll keep an eye on that, at least I know what it is.

But something still isn't right though. I tried the GC again and nothing (black screen, no flicker, no odd noise) then I tried it with my regular Tetroid Trump clone, also nothing! But it seemed to work (i.e. boot) without the Trump and with a different ROM selected from ROM switcher switch. It didn't seem to like the Minerva ROM for some reason, all the others were ok. Eventually after a few pull-outs and plug-ins of the Trump card it started working again.

I suppose that's likely to mean the connector needs a good clean, both on the QL and in the socket on the Trump/GC?

[RWAP]

Do be careful that you are not bending any pins in the QL expansion connector - that is very easily done unfortunately.

With certain combinations between a Gold Card and ZX8301 you may need to remove the QL's 68008 to get the Gold Card to work.

[Chr$]

With certain combinations between a Gold Card and ZX8301 you may need to remove the QL's 68008 to get the Gold Card to work.

That's very interesting actually. The pins are all fine and the GC works fine too (in the original beast it was housed and in a Spanish QL, which has the earlier ZX8301) but it simply refuses to boot in my German QL with the later ZX8301. I've tried changing the ROM switcher from Minerva back to MGG. I even tried the original 2 MGG ROM chips. Same thing. The only added hardware it has is a vMAP, but that can't be the issue I don't think. I don't think I actually tried it with the original QL CPU removed.