Hi folks,

I've dug out all my EP stuff again after FAR too many years and I'm sadly not surprised to see some things have failed given the age of the components. Thanks to this forum (hi Zozo  ) I've already fixed a video problem with my main ep64 and the ep128 came back to life by itself so I'm expecting that one to fail again soon, probably dried out capacitors.

Main issue I have at the minute is none of my expansion boards work any more and I'm trying to find the common problem between them all. I have at least 2 EXDOS modules, the original Spectrum Emulator and 3 bridge boards but none of them seem to work any more and I can't remember the mechanism that detects the expansion board.

Voltages are OK and the bridgeboard's 7805 is generating +5V for the expansion boxes. I haven't dared to open the EXDOS modules as they're still 'as new' but if they have died over time I'm going to have to. I'm using the same Spectrum+2 PSU I did last time all this kit was at an exhibition in 2005.

Thinking about it I also have a couple of old prototype HDD cards, I'll dig those out too.

Any clues?

Cheers!

Hi Zozo,

Nice to be back!

I remember the TVC, I recently found the pictures you sent all those years ago when I was clearing up the hard drive of my webserver and realised that machine would be long gone by now. September 2008 that was.... From the hardware summary it was closer to a Camputers Lynx than an EP? Still a nice looking machine though

The last exhibition I did was in Croydon UK 2005, the EPs I had on show were put in their box and not opened again until last month, nice to see the flashing ENTERPRISE screen again! You're onto something with the contacts, with the case of a UK bridge removed and the top of the EP shifted slightly I got the nice pause while it looked for a floppy then :help showed EXDOS

So I put everything back together again and....nothing. Tomorrow I'll shift the motherboard slightly and try the Hungarian bridge again, according to my pictures that's how I ran it back then so fingers crossed. I'm wary of messing with this particular EP128 since it's one of the original factory upgraded 64s.

Cheers!

It is still waiting for you!

Really? Wow!

Great! Then I think no any serious problem. Just need to find the right position. Contacts cleared?

Not yet, that's the plan for tonight, I'm also hoping the board will shift by 1mm or so and that will be enough. I still haven't perfected a method of re-inserting the keyboard ribbon cables without fear of damage.

W

OK, I can't get consistency out of the 128 unless I have the top cover off which makes plugging the keyboard in awkward. I've also discovered whilst trying to load things off floppy that the bottom left row of keys doesn't work which means a fault on the right-hand keyboard connector which LOOKS fine. New membrane time?

Time to get out the unused 128 and see if it works as it should; be interesting to see if the bridge will work without its case off!

Hello matey,

Nice to see you on here!  Time to get them EPs working!

If they are original membranes then time for a shiny new one!

R

Is any news?

OK, finally time to look at this board and straight away noticed that TR4 will wobble the screen when touched or tapped. Standard 3904 or so it seems. The soldering looked well dodgy:

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so I reflowed it. Still the same. Rummage in my bits box and find another 3904 but I get full-on wobble with that one in place. Odd. Put original back in and it's fine until it's tapped (or, I guess, heats up in use). Find a spare EP64 board that's previously been robbed of bits and use TR4 from that, still the same screen breakdown. Put original back in and all is good so over to the transistor tester.

Original as seen in the pic: hFE 213, Vf 718mV
Replacement from spare board: hFE 433, Vf 674mV

Both 3904s so why the big difference?

W