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Author Topic: Enterprise 64 dead (Read 206 times)

Offline neurox

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  • Country: dk
Enterprise 64 dead
« on: 2024.May.01. 12:44:37 »
Hi!

A couple of years ago, I bought my second Enterprise 64, ISSUE 4, S/N 030391. It worked for a brief moment, and then died on me. In an attempt to fix it, I replaced the capacitors, voltage regulators and socketed the RAM and CPU to allow for testing other components. Nothing seemed to work - screen was blank, as far as I recall. Today I took a leap and powered it up with the same setup as I recently tested another Enterprise on - stabile original power supply and a SCART->HDMI converter. The result was white/black vertical stripes. No sound.

I reached out to Zozo a couple of years ago, and while he suggested a number of checks I could do, I never managed to get the system working. As far as I recall, power levels were good and the CPU was receiving a clock signal.

I'm not sure where to go from here - obviously I'd love to get the system working again, but while I do have both a soldering iron and a digital scope, I don't have a lot of experience fixing computers. If you have any suggestions on where to probe and what to look for, I'd be happy to provide screenshots if anyone wants to help me out :-)

Regards,
HC
Hans Christian Saustrup
Mastodon: https://mstdn.dk/@saustrup

Collection:
EP S/N 000828 - 64K+256K (wirewrapped!) - Works
EP S/N 030391 - 64K - Dead
EP S/N 030490 - 64K+1024K - Works
SD-Card Premium Cartridge (works)
Original EXDOS Controller (works)


Offline neurox

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  • Posts: 8
  • Country: dk
Re: Enterprise 64 dead
« Reply #2 on: 2024.May.01. 13:16:04 »
Wow, plenty to read and test - thanks! :-)

Slava Ukraini!
Hans Christian Saustrup
Mastodon: https://mstdn.dk/@saustrup

Collection:
EP S/N 000828 - 64K+256K (wirewrapped!) - Works
EP S/N 030391 - 64K - Dead
EP S/N 030490 - 64K+1024K - Works
SD-Card Premium Cartridge (works)
Original EXDOS Controller (works)

Offline SlashNet

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  • Country: ua
  • Enterprise 128K | Cubietruck
    • My old site about Enterprise
Re: Enterprise 64 dead
« Reply #3 on: 2024.May.01. 13:46:22 »
Wow, plenty to read and test - thanks! :-)

Slava Ukraini!

You're welcome. ;-)

Offline neurox

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  • Posts: 8
  • Country: dk
Re: Enterprise 64 dead
« Reply #4 on: 2024.May.01. 14:24:05 »
Small, fruitless update:

Just tested with a couple of other brand new CPUs from a trusted supplier, as well as with the myriad of EPROMs I made while testing with Zozo a while back.
Same result - black and white bars. If I remove one memory chip, I get black and red bars. Another, and I get black and green bars. No sound.

CPUs tested:
- Zilog Z84C0006PEG (original)
- Zilog Z84C0006PEG (brand new)
- Zilog Z84C0010PEC (brand new)

ROMs tested:
- EXOS 2.1
- "TEST1"
- "TEST2"
- "REGTEST"
- "VRAM"
- "VRAM TEST"
(I seem to recall one of them being the beep-test)

Memory chips are KM4164B-12-227C.
Hans Christian Saustrup
Mastodon: https://mstdn.dk/@saustrup

Collection:
EP S/N 000828 - 64K+256K (wirewrapped!) - Works
EP S/N 030391 - 64K - Dead
EP S/N 030490 - 64K+1024K - Works
SD-Card Premium Cartridge (works)
Original EXDOS Controller (works)

Offline Zozosoft

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  • EP addict
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  • Posts: 14743
  • Country: hu
    • http://enterprise.iko.hu/
Re: Enterprise 64 dead
« Reply #5 on: 2024.May.01. 15:42:23 »
Z80 RD,MREQ,M1 are active? And ROM chip CE,OE?

It is looks the ROM not running.
Worst case if Dave dead :cry: Better if only ROM signal missing from Dave, can be substitued with few 74 chips.

Better case if some mechanical signal problems: contact problem at ROM socket. Broken via somewhere on board. SMD contact problem at Dave pins.

Offline Judge

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  • Posts: 693
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Re: Enterprise 64 dead
« Reply #6 on: Yesterday at 17:24 »
OFF! Tudom, hogy erősen off, de muszáj ide is írnom, hátha ez a kedves "neurox" ezt a topicot hamarabb hajlandó nézni a saját érdekében.
Rendelt tőlem két kábelt amivel kapcsolatban egyeztetnünk kellett volna, de nem reagál a kedves úr semmire, bár úgy látom ide se írt azóta.

Hi "neurox", contact me in private message (Judge)
Üdv.Judge

Offline neurox

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  • Country: dk
Re: Enterprise 64 dead
« Reply #7 on: Yesterday at 20:35 »
Let me put things completely straight here - I wrote "Judge" and asked for a quote for two cables. He replied with questions regarding length etc., which clearly means that we have not finished our negotiation, and as such do not have any kind of deal yet. In fact, no details about payment or shipping have even been exchanged at this point.

This was three days ago. I failed to answer him, because - like many of you here - the Enterprise is not a full time job for me. I do have other obligations, and I do not always have the opportunity to reply within days or - on rare occasions - even within weeks.

Google Translate might be failing me here, but I see absolutely no reason to threaten me with expressions like "for his own sake". I have been registered with this forum for six years and have always been polite and friendly towards to members of this community and I'm frankly a little surprised by this outburst.

And Zozo, I do appreciate your suggestions for finding the issue with my board. I will try it out with I have time. Thank you again.
Hans Christian Saustrup
Mastodon: https://mstdn.dk/@saustrup

Collection:
EP S/N 000828 - 64K+256K (wirewrapped!) - Works
EP S/N 030391 - 64K - Dead
EP S/N 030490 - 64K+1024K - Works
SD-Card Premium Cartridge (works)
Original EXDOS Controller (works)

Offline Judge

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  • Posts: 693
  • Country: hu
Re: Enterprise 64 dead
« Reply #8 on: Yesterday at 22:23 »
Google Translate might be failing me here, but I see absolutely no reason to threaten me with expressions like "for his own sake". I have been registered with this forum for six years and have always been polite and friendly towards to members of this community and I'm frankly a little surprised by this outburst.

You misunderstood me. I wasn't rude to you. You should have just written that you don't have time right now. Other people's problem was that if I didn't write back in time.

Tamás, ha gondolod törölheted az én offomat innen, mert megbeszéljük privátban és itt pedig elnézést kérek tőletek! Eddig már körbeküldtem a világot a kiegészítőimmel és még senkivel nem volt ilyen konfliktusom. Már Dániába is küldtem ezelőtt két srácnak.
Üdv.Judge