No load bars

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No load bars

Post by petercushion » Sun Jul 28, 2019 12:46 pm

Hi all,

first time posting newbie here :roll:

I've got two Speccys, one works fine. I bought a second one to do up and I've done a composite mod and replaced the keyboard membrane (and given it a good clean) but when I plug the mono gable in to the ear jack, it doesn't 'listen'. I read that I should start with IC1 5C112/6C001 ULA but quite honestly, I don't know what that is. Can anyone point me in the direction of some help? Everything I've done so far, I've learnt from YouTube videos and websites so if anyone can suggest a guide, that would be really appreciated!

Thank you :)

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Re: No load bars

Post by 1024MAK » Sun Jul 28, 2019 2:00 pm

Hello Peter, welcome to our forum :D

Which issue board is it (printed text near the front edge of the board)?

The audio level required for loading is not the same across all the different versions of the board or the different ZX Spectrum models. So do try other volume levels.

By the way, are you using a cassette deck, a PC / laptop or other modern device as the audio source?
Modern devices limit their audio outputs, so loading can be marginal even at maximum volume.

Can you also please post up a good quality photo of your board.
petercushion wrote:
Sun Jul 28, 2019 12:46 pm
IC1 5C112/6C001 ULA
This is a large 40 pin DIL (Dual In Line) integrated circuit (or IC) often referred to as a ‘chip’.
On the layout diagram (note, different for each issue board) and on the silk screen (printing on the top of the board) it will be labelled next to the chip as ‘IC1’. On the top of the chip, it will be labelled with the part number, 5C112 and 6C001 are each part of the range of part numbers, as there were various versions. Alas, the supply of original spares dried up long ago. There are replacement modules though.

But if the Spectrum is otherwise working fine, it is less likely that IC1, the ULA, is faulty.
So the next step would be to check the Ear socket to make sure that the contacts are clean, that they make good contact when a 3.5mm jack plug is inserted and also check on the underside of the board for any broken or cracked PCB tracks. Also check the solder joints that hold the Ear socket. They should be a bright shiny silver colour, with no signs of cracks or rings and no lumpy distortions. If you are not sure, post up a photo.

To add photos, use the Attachments tab below the edit box.


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Re: No load bars

Post by petercushion » Sun Jul 28, 2019 7:27 pm

Hi Mark,

thanks for the warm welcome! :)

the board issue is 3.

I'm using an android phone and an 'app' called PlayZX. It worked fine with the other Speccy, so I assumed it would work just as well with the new one but nothing after I type the command to load the game.

So do you think the issue could be with the app and the phone? Could the volume be too high?

Please excuse the capacitor poking out of the RF module! :oops:

Thanks again!

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