EPROM cart won’t catalogue and caused hard reset

Discussion forums for users of the Cambridge Z88 Portable Computer
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okto
Posts: 28
Joined: Sat Apr 22, 2023 7:48 am

EPROM cart won’t catalogue and caused hard reset

Post by okto »

I have a 32k EPROM cart that previously had PCLink burned on it, so I know it works.

I have run it through an EPROM eraser three times for a total of an hour and a half of exposure; it still will not catalogue.

Today, after the third erase cycle, I plugged it in (after switching to Index like I’m supposed to), and the screen blacked out and flickered and the machine hard reset, losing a bunch of work.

What gives!?
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Flatulentia
Posts: 93
Joined: Sun May 14, 2023 3:58 pm
Location: Cambridgeshire, UK

Re: EPROM cart won’t catalogue and caused hard reset

Post by Flatulentia »

I believe it is possible to kill an EPROM with too much UV. There's a limit to how many times you can erase them due to the damage it does.
ZX81 with ZiLOG Z84 CMOS Z80, 32KB battery-backed Toshiba 55257 SRAM with charge status LED, Wilf's "Why Wait?" mod and switch-mode 5V regulator. 50/60Hz mode switch, composite video output with Zigg's back porch mod and 1080p60 HDMI output.
Jbizzel
Posts: 65
Joined: Thu Apr 23, 2020 6:58 pm

Re: EPROM cart won’t catalogue and caused hard reset

Post by Jbizzel »

A known problem is leaving eprom cards in z88s without power. Apparently that can lead to them being corrupted?? It's written about on the Rakewell shop site
okto
Posts: 28
Joined: Sat Apr 22, 2023 7:48 am

Re: EPROM cart won’t catalogue and caused hard reset

Post by okto »

Sounds like it's time to whip out the desoldering tool.
okto
Posts: 28
Joined: Sat Apr 22, 2023 7:48 am

Re: EPROM cart won’t catalogue and caused hard reset

Post by okto »

Very belated update: it turns out the Chinesium EPROM eraser just wasn’t strong enough, so the cartridge wasn’t actually erased. I’ve since acquired a metal-bodied good ol American-made EPROM eraser that did the trick with about 15 minutes of exposure, and the cartridge works fine now.

Now I just have to get >=128k in the machine so I can run RomUpdate and blow EazyLink into it.
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