The Sinclair QL Forum

And here are some decent pics of the Q40 board, taken just before mounting it onto a new home.

Top: Bottom: Bottom detail (someone called P. Graf ) An angle: Another angle: A few more questions spring to mind... What do the yellow stickers indicate (1.0?), if anything? Are the lithium Timekeeper battery/RAM devices known to leak at all? The m/b says V2, so how does it differ to V1? And most importantly, are those big rubber feet an original feature?

Hi Chr$,

Nice pictures, the Q40 board looks to of been a Tony Firshman/Qbranch board.

The Q40 board will allow up to 32Mb Fastpage ram modules as detailed in the Q40 Manual.

The heat sink on the 68040 CPU looks like it has been removed and incorrectly refitted. I would check the heat sink is in contact with the CPU.

All the boards made for the Q60 and Q40i, were v2 PCBs, VRAM chips were soldered direct to the board.

I have not seen the clock batteries lleak, only need replacing at an appropriate time, when the clock is not holding the time correctly.

The yellow stickers indicate the number of IC chip and some sort of version number. The isp1016 chips probably programmed by Tony Firshman.

Derek_Stewart wrote:Hi Chr$,

Nice pictures, the Q40 board looks to of been a Tony Firshman/Qbranch board.

The Q40 board will allow up to 32Mb Fastpage ram modules as detailed in the Q40 Manual.

Yes, normally it has 32mb fitted, I removed it and the eproms for the pics.

Derek_Stewart wrote:The heat sink on the 68040 CPU looks like it has been removed and incorrectly refitted. I would check the heat sink is in contact with the CPU.

It does indeed look a bit wonky, I suspect it was fitted that way originally. I'm sure it's doing it's job as it has certainly been in use over the years with no adverse effects.

Derek_Stewart wrote:All the boards made for the Q60 and Q40i, were v2 PCBs, VRAM chips were soldered direct to the board.

My VRAMs appear to be socketed.

Derek_Stewart wrote:I have not seen the clock batteries leak, only need replacing at an appropriate time, when the clock is not holding the time correctly.

It seems to hold the time for 3-4 days max. I'll have to see if there is a suitable replacement.

Derek_Stewart wrote:The yellow stickers indicate the number of IC chip and some sort of version number. The isp1016 chips probably programmed by Tony Firshman.

Ok, yes I suppose they all look the same so needed some kind of identification so they were fitted in the right places.

Wow, Q40 dates back to 1997 according to that photo of the circuit board! Honestly did not think the design was that old!

Chr$ wrote:A few more questions spring to mind... What do the yellow stickers indicate (1.0?)

IC reference designator and logic version.

Chr$ wrote:Are the lithium Timekeeper battery/RAM devices known to leak at all?

No.

Chr$ wrote:The m/b says V2, so how does it differ to V1?

V1 was the prototype. It was a two-layer board and worked only up to 25 MHz with slower DRAM timings.

Chr$ wrote:And most importantly, are those big rubber feet an original feature?

Not all all.

Chr$ wrote:It seems to hold the time for 3-4 days max. I'll have to see if there is a suitable replacement.

You can use: M48T02-70PC1 or M48T02-150PC1
In stock at the major distributors like Mouser, etc. If you like, I can get one for you, the next time I order something anyway.

dilwyn wrote:Wow, Q40 dates back to 1997 according to that photo of the circuit board! Honestly did not think the design was that old!

Yes, and that was already the Q60 PCB, also. Just that the 68060 was still so expensive, I decided to start with the 68040.

Peter wrote:You can use: M48T02-70PC1 or M48T02-150PC1
In stock at the major distributors like Mouser, etc. If you like, I can get one for you, the next time I order something anyway.

Yes, that would be great, please do. Pop it in with the PLCC44 replacement, once I've sorted that out. I will of course include suitable reimbursement for costs and time. Thanks.

And I'll lose those rubber feet then! I don't need them with my new arrangement, clearance underneath is good.

Hi,

The purpose of the rubber feet is an attempt, to support the PCB from be flexed from inerstion of a Card into the ISA sockets.

I have repaired Q40 boards were there has been damage to the internal circuit traces, around the ISA connectors.

There should also be support under the Rom and Ram Sockets, which may also introduce flexing of the PCB, when inserting ram modules.

Seems to be a quality problem of the PCB. I have had never such problems with PC mainboards when inserting RAM modules or ISA cards.

Derek_Stewart wrote:Hi,

The purpose of the rubber feet is an attempt, to support the PCB from be flexed from inerstion of a Card into the ISA sockets.

I have repaired Q40 boards were there has been damage to the internal circuit traces, around the ISA connectors.

There should also be support under the Rom and Ram Sockets, which may also introduce flexing of the PCB, when inserting ram modules.