Testbook 1 alternatives

[paul.adshead]

A touch screen CRT, cool.

Just keep away from the 'hot' end (- that's at 30KV)!!

[marinabrian]

A touch screen CRT, cool.

Just keep away from the 'hot' end (- that's at 30KV)!!

Hi Paul, it's not the EHT , nor the X-rays that worry me, it's the wife reaction to the dessecration of her kitchen, and getting a hernia lugging it about !
Brian.

[marinabrian]

Right, the PSU is now sorted , turns out that a common anode fast recovery rectifier diode in a TO220 package, was at fault, but now on power up, I have lines on the display, long beep, followed by 5 short beeps, corrupted bios perhaps?
Now the bios is on a 1 meg eprom, & I have access to an eprom programmer, AND a friendly chap who has graciously allowed me to copy his prom, but just to save me a long journey, does anyone have any other ideas? I just don't want to have a 800 mile round trip if I'm missing something silly
Suggestions on a postcard please
Cheers
Brian.

[BBS SPY]

Could be the Video Bios, have you tried reverting to OEM Video?
other than that, as you have a bios image already, not much i can offer i am afraid.

[marinabrian]

Hi Colin, I don't exactly have the Bios image just yet!, just the offer of copying the eprom from another machine, not so handily located 400 miles from home , If you have an image of AMIBIOS 486DX ISA BIOS to hand I would really appreciate it if you could email it to me! , having said all this, the "Beep" code is meaningless to me, and not having a meaningful display,i.e. no text, is none to reassuring, to say the least
As to the display, I do have an ancient isa graphics card to hand
Any ideas on what the beep code might mean?
Cheers
Brian

[marinabrian]

Could be the Video Bios, have you tried reverting to OEM Video?
other than that, as you have a bios image already, not much i can offer i am afraid.

Hi Colin, how do you disable the video bios, and revert to oem video then, as it looks like the cirrus logic onboard video has given up the ghost, and although I'm reasonable handy with a soldering iron, a SM i.c. with a zillion pins is a bit beyond me . I was thinking it may be possible to utilise an old ISA display card I have, in place of the LAN card, which let's face it doesn't exactly do much does it?
Cheers
Brian.

[BBS SPY]

Hmmn, not sure, its either in the Bios or one of those un marked jumpers methinks.

You would likely have to put in a replacement video card though.
Yea the slot where the Lan was, seems like as good as any

[paul.adshead]

Most PCs/video cards, default to a low resolution (VGA) if they can see each other during power on. I'd just try putting it in and connecting your screen. If it doesn't work you haven't lost anything.

[nsxxtreme]

Can you just fix the power supply? PSU usually are not that complicated, and its usually the switching transistors that burn up. Usually you can replace those and your good to go. You seem to be into that kind of thing maybe you can try that?

Never mind I see you fixed it. The fast recovery diodes are the other common failures. Make sure its replaced with another fast recovery diode or it will fail again very shortly (if it even works at all).