PCB containing Z80 ++ devices - UK Vintage Radio Repair and Restoration Discussion Forum

Wendymott · 24th May 2023, 1:19 pm

Hi Peeps. Further to my previous post re thermal printer.. I decided to let the main processor pcb go. It contains 2 X Z80, 2 X CTC, 4 X PIO, + Memory and a couple of Proms.
£10 the lot.. + Postage say £5 First come etc etc.. I seem to think these parts are sought after by the Puter Bods.
Please PVT message me if wanted

SiriusHardware · 24th May 2023, 1:37 pm

I don't need these for a specific purpose Wendy, but if it gets to the point where you are about to WEEE the PCB due to lack of interest I will rescue it. I will defer, initially, to anyone else interested.

You took a really nice, well lit and well focused shot from directly overhead but that does make it difficult to see whether some or all of the ICs are in sockets. The EPROMs do appear to be, but are the rest?

Wendymott · 25th May 2023, 10:27 am

Hi Sirus. Only the Z80 processors and ROMs are in sockets the rest are soldered.

SiriusHardware · 25th May 2023, 10:50 am

I have good desoldering gear and would have no problem desoldering them and holding them as spares, possibly for other people on the forum to use in the future, so I'd be happy to take the PCB complete and on your original terms despite the fact that many of the devices are soldered in.

My main concern was that you might get no takers and dispose of the PCB, which would be a bit of a waste as the PIOs and CTCs are useful Z80-family ICs and somewhat less common than the Z80 CPUs themselves.

Techman · 25th May 2023, 1:10 pm

I was looking at this board on offer in the hope that it contained a certain variant of the Z80 as shown below. I need several, probably up to half a dozen to keep me going. Concentrated heating of the chip cures the fault and then freezing of just the chip alone causes the fault to return, therefore narrowing the fault down to the chip itself in the light of there being no surrounding circuit information available. I've got at least four of these boards, all with exactly the same fault. Extreme heating of the chip will cause it to work for up to a week or two, but it will then fail again with the same fault.

Wendymott · 25th May 2023, 2:48 pm

Hi Techman. Please see photo. If its what you need ok.

Mark1960 · 25th May 2023, 3:13 pm

Quote:

Originally Posted by Techman

I was looking at this board on offer in the hope that it contained a certain variant of the Z80 as shown below. I need several, probably up to half a dozen to keep me going. Concentrated heating of the chip cures the fault and then freezing of just the chip alone causes the fault to return, therefore narrowing the fault down to the chip itself in the light of there being no surrounding circuit information available. I've got at least four of these boards, all with exactly the same fault. Extreme heating of the chip will cause it to work for up to a week or two, but it will then fail again with the same fault.

Thats not a z80, quick search shows it as a Motorola voltage controlled oscillator.

SiriusHardware · 25th May 2023, 4:04 pm

I find similar results when looking but note the ceramic resonator close by the chip. There are other results suggesting that 'ZC' is a common Motorola prefix for mask programmed microcontrollers. I think that is what it is and it may possibly run Z80 code but is much more likely to run some flavour of 68xxx code given that the manufacturer is Motorola. I'm afraid there won't be any of those on Wendy's PCB.

For the avoidance of confusion, the one in Wendy's post #6 -IS- a Z80 CPU. I think Mark was referring to the one in Techman's photo in #5.

Techman · 26th May 2023, 2:05 am

Quote:

Originally Posted by Wendymott

Hi Techman. Please see photo. If its what you need ok.

Thanks Wendy, but it seems from discussions that this won't be suitable for what I'm looking for.

SiriusHardware · 26th Jun 2023, 10:59 am

Wendy, have you decided to dispose of the parts on this PCB separately or is it still available on the original terms?

Wendymott · 28th Jun 2023, 11:20 am

Hyas Sirius.. Ooopppssss...I had totally forgotten about this post.. Yes you can have it for the original, as per posting.
Please PM me with your details and we can come to some arrangement

SiriusHardware · 28th Jun 2023, 9:54 pm

Hi Wendy, only just caught this, sorry. I will PM you now.

SiriusHardware · 3rd Jul 2023, 12:40 pm

Thanks to Wendymott I'm now the custodian of this PCB full of useful Z80 system ICs. In addition to the 2 x socketed (non-A) Z80 CPUs and 2 x socketed 27C128 EPROMs it also contains the following interesting soldered-in ICs:

4 x Z80-PIO, 2 x Z80-CTC, 2 x low-power 120nS 6264 RAMs, 1 x MM5450 (which I think is a serial input to parallel output LED driver IC) 1 x MM58274 RTC clock IC and its associated crystal and trimmer capacitor, 5 x metal cased BSX20 transistors and one metal cased 2n2894 transistor.

I'm going to keep it intact as it will be easier to remember where all these parts are if I leave them in the PCB, the only thing I have already removed is the battery which, when I did remove it, already had a pool of electrolyte under it which had started to etch away the tracks underneath the battery.

If anyone ever has a specific need for any of these ICs please PM me, but please only ask if you really need one, bearing in mind that the majority are soldered in.

24th May 2023, 1:19 pm	#1
Wendymott Octode Join Date: Jun 2013 Location: Huddersfield, West Yorkshire, UK. Posts: 1,730	PCB containing Z80 ++ devices Hi Peeps. Further to my previous post re thermal printer.. I decided to let the main processor pcb go. It contains 2 X Z80, 2 X CTC, 4 X PIO, + Memory and a couple of Proms. £10 the lot.. + Postage say £5 First come etc etc.. I seem to think these parts are sought after by the Puter Bods. Please PVT message me if wanted Attached Thumbnails __________________ Should get out more. Regards Wendy G8BZY

24th May 2023, 1:37 pm	#2
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 10,833	Re: PCB containing Z80 ++ devices I don't need these for a specific purpose Wendy, but if it gets to the point where you are about to WEEE the PCB due to lack of interest I will rescue it. I will defer, initially, to anyone else interested. You took a really nice, well lit and well focused shot from directly overhead but that does make it difficult to see whether some or all of the ICs are in sockets. The EPROMs do appear to be, but are the rest?

25th May 2023, 10:27 am	#3
Wendymott Octode Join Date: Jun 2013 Location: Huddersfield, West Yorkshire, UK. Posts: 1,730	Re: PCB containing Z80 ++ devices Hi Sirus. Only the Z80 processors and ROMs are in sockets the rest are soldered. __________________ Should get out more. Regards Wendy G8BZY

25th May 2023, 10:50 am	#4
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 10,833	Re: PCB containing Z80 ++ devices I have good desoldering gear and would have no problem desoldering them and holding them as spares, possibly for other people on the forum to use in the future, so I'd be happy to take the PCB complete and on your original terms despite the fact that many of the devices are soldered in. My main concern was that you might get no takers and dispose of the PCB, which would be a bit of a waste as the PIOs and CTCs are useful Z80-family ICs and somewhat less common than the Z80 CPUs themselves.

25th May 2023, 4:04 pm	#8
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 10,833	Re: PCB containing Z80 ++ devices I find similar results when looking but note the ceramic resonator close by the chip. There are other results suggesting that 'ZC' is a common Motorola prefix for mask programmed microcontrollers. I think that is what it is and it may possibly run Z80 code but is much more likely to run some flavour of 68xxx code given that the manufacturer is Motorola. I'm afraid there won't be any of those on Wendy's PCB. For the avoidance of confusion, the one in Wendy's post #6 -IS- a Z80 CPU. I think Mark was referring to the one in Techman's photo in #5.

25th May 2023, 1:10 pm	#5
Techman Dekatron Join Date: Nov 2009 Location: Lincolnshire, UK. Posts: 4,744	Re: PCB containing Z80 ++ devices I was looking at this board on offer in the hope that it contained a certain variant of the Z80 as shown below. I need several, probably up to half a dozen to keep me going. Concentrated heating of the chip cures the fault and then freezing of just the chip alone causes the fault to return, therefore narrowing the fault down to the chip itself in the light of there being no surrounding circuit information available. I've got at least four of these boards, all with exactly the same fault. Extreme heating of the chip will cause it to work for up to a week or two, but it will then fail again with the same fault. Attached Thumbnails

25th May 2023, 2:48 pm	#6
Wendymott Octode Join Date: Jun 2013 Location: Huddersfield, West Yorkshire, UK. Posts: 1,730	Re: PCB containing Z80 ++ devices Hi Techman. Please see photo. If its what you need ok. Attached Thumbnails __________________ Should get out more. Regards Wendy G8BZY

26th Jun 2023, 10:59 am	#10
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 10,833	Re: PCB containing Z80 ++ devices Wendy, have you decided to dispose of the parts on this PCB separately or is it still available on the original terms?

28th Jun 2023, 11:20 am	#11
Wendymott Octode Join Date: Jun 2013 Location: Huddersfield, West Yorkshire, UK. Posts: 1,730	Re: PCB containing Z80 ++ devices Hyas Sirius.. Ooopppssss...I had totally forgotten about this post.. Yes you can have it for the original, as per posting. Please PM me with your details and we can come to some arrangement __________________ Should get out more. Regards Wendy G8BZY

28th Jun 2023, 9:54 pm	#12
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 10,833	Re: PCB containing Z80 ++ devices Hi Wendy, only just caught this, sorry. I will PM you now.

3rd Jul 2023, 12:40 pm	#13
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 10,833	Re: PCB containing Z80 ++ devices Thanks to Wendymott I'm now the custodian of this PCB full of useful Z80 system ICs. In addition to the 2 x socketed (non-A) Z80 CPUs and 2 x socketed 27C128 EPROMs it also contains the following interesting soldered-in ICs: 4 x Z80-PIO, 2 x Z80-CTC, 2 x low-power 120nS 6264 RAMs, 1 x MM5450 (which I think is a serial input to parallel output LED driver IC) 1 x MM58274 RTC clock IC and its associated crystal and trimmer capacitor, 5 x metal cased BSX20 transistors and one metal cased 2n2894 transistor. I'm going to keep it intact as it will be easier to remember where all these parts are if I leave them in the PCB, the only thing I have already removed is the battery which, when I did remove it, already had a pool of electrolyte under it which had started to etch away the tracks underneath the battery. If anyone ever has a specific need for any of these ICs please PM me, but please only ask if you really need one, bearing in mind that the majority are soldered in.