Memotech HRG ROM/PAL dumps?

Discussions about Sinclair ZX80 and ZX81 Hardware
Moggy
Posts: 3493
Joined: Wed Jun 18, 2008 2:00 pm

Re: Memotech HRG ROM/PAL dumps?

Post by Moggy »

As promised just had a quick run through with mine and all ok.

I can only think in your case that the connection between the ram-pack and the HRG module is not too good.
When you power up do you see the "K" cursor instantly or after a few seconds? If instantly then the Zeddy isn't seeing the extra memory.

With everything in place type PRINT PEEK 16388 +256 * PEEK 16389 and if all is ok you should see 32768 as a result, if it's 17408 then only 1k is being recognised.

Other than bad connections I can only think the internal 1k is shot which the HRG unit needs to function.

A picture of one of the test programs. The Zeddy I used was running in inverse mode hence the white on black. In normal mode the HRG unit prints the usual black ink,white paper.
Attachments
HRG.JPG
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GrantmeStrength
Posts: 4
Joined: Fri Nov 29, 2024 4:27 pm

Re: Memotech HRG ROM/PAL dumps?

Post by GrantmeStrength »

Both the internal and external memory is working just fine, which makes me think it's more serious - and the HRG board itself has a fault.

I will keep probing with the oscilloscope but really that's just shooting in the dark at this point.

Thanks for the response!
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