opened E-bay conversation IF1 not working

[larryl79]

Hi Tom!

We started a conversation on e-bay about my IF1 not working. I cleaned the contacts on the spectrum bus, and the MD port of the IF1 but no change, still same issue. how can I identify the rom version of my IF1?

[larryl79]

I fond this in one document:

Run the following line of BASIC:

CLOSE # 0: PRINT PEEK 23729

If this prints out a '0', then you have an edition 1 Interface 1. if it prints out '80', you have an edition 2 Interface 1. gives back 0 so should be rom V1, but I got response 0 even if IF1 isn't connected.

[TomDDG]

Hi. I think your IF1 maybe broken. The commands you ran earlier failed to page in the Shadow ROM correctly so checking which version will not work as that needs the Shadow ROM to work. The "RUN" command after the "PRINT p" command should've have returned "Program Finished, 0:1" not "0 OK, 0:1". Do other peripherals work when attached like a DivIDE or even a simple Kempston Joystick interface? If they do that rules out any issues with your Spectrum.

Can you open up your IF1 and check it looks ok, sometimes the ULA can overheat and fail and you maybe able to see something, even attach a photo if you can. Also do the Capacitors look ok, no leaking?

[larryl79]

visually IF1 board is ok. There's a sign of ULA (over)heating on the casing of IF1 I ran my ZX for an hour at least while I entered a basic program from documentation, but after all the IF1 ULA is almost cold.

I've got a homemade single joy port interface, but I don't know yet how to test it without anything. [edit] joystick interface works with a next simple tester:

10 PRINT AT 0,0;IN 31,
20 GO TO 10

I think I need some edge interface extension cable to make measurements on the IF1 interface board

[TomDDG]

It does sound like the Spectrum is ok and the ULA in the IF1 isn't. Obviously can't rule out any other issues but it is usually the ULA that goes. There are replacements online, Charlie sells a modern replacement (https://vdrivezx.com/vla1-sinclair-interface-1-ula-replacement/) which you can get from a few online retailers. Can't guarantee it is that but that would be my guess based on the fact the shadow ROM isn't being paged in correctly.

[larryl79]

I seen his shop already, I think I seen another source directly form UK.

just attaching the pics (I forgot last night.)

[TomDDG]

Yeah I think it is the ULA!

[larryl79]

When I got it 1st time it was running, but the zx internal psu was crap... and the zx wasn't in working condition (i didn't aware of it, seller said everything working). do you think that killed the IF1?

[TomDDG]

ULAs in Spectrums & IF1 are well known for dying and overheating is often the reason. Lots of people put heatsinks on them for this reason. It could've just been ready to go when you got it or the power issues pushed it too far. Unfortunately difficult to say. The heat mark on the IF1 case is a sure sign that the ULA overheated and died. I'd recommend a vLA1 from Charlie or if you want it fully serviced so you know it will definitely work, Mutant Caterpillar offer a full service. https://www.mutant-caterpillar.co.uk/shop/product_info.php?products_id=3664

[larryl79]

I think I'll be happy with this product, I'll get back about results. It's more fun to do it for myself :)

http://retrorevivalshop.co.uk/index.php?main_page=product_info&cPath=5&products_id=559

[Update] Part arrived, but still doesn't work. I waiting to another IF1 to arrive.