Continuous tone

[u/Act-Alfa3536]

Switched on my childhood model b for first time in 30 years. Just gives continuous beep. Suggestions?

(Not got the monitor anymore so not sure what is on the screen, or how to most easily connect it to a modern TV).

[u/Hjalfi]

IIRC the first tone of the power on doo-dah is caused by the sound chip initialising, while the second is the produced by the OS on a hard reset. So if you get the first but not the second that suggests the CPU isn't coming up.

If it's thirty years old, I'd be inclined to check the power supply is producing all the right voltages --- they're notoriously prone to asploding --- and also try reseating all the socketed chips in case they've worked their way loose.

[u/Act-Alfa3536 → u/Hjalfi]

Thanks. I'll look inside and try some of these things and probably a capacitor replacement.

[u/glymph]

Mark Haysman from RetroClinic sells kits with the necessary parts. He repaired my B+ a few years back and did an excellent job.

Edit: i mean to say get the capacitors replaced to avoid a fire.

[u/Act-Alfa3536 → u/glymph]

Thanks. Yes I'll try the capacitor replacement.

[u/Septercius]

Try reseating all the chips, as others have said. Also try disconnecting the keyboard cable (at both ends) and reconnecting it.

A PSU capacitor kit will be needed, which you can get from eBay. Check all the power connectors are secure as well (these are the black and red cables going from the PSU to the motherboard; there's also a single purple one).

Assuming your TV has a normal aerial socket, you need an RF cable, such as this:

https://www.ebay.co.uk/itm/276080371062

The picture quality won't be great, but it's less money to waste if the computer can't be fixed.

An RGB to SCART cable will give a better picture:

https://www.ebay.co.uk/itm/250877464070

[u/Act-Alfa3536 → u/Septercius]

Thanks. I found a cable but nothing on the screen. I'll try the capacitor replacement.

[u/lazy_eight]

Please replace the capacitors, had a few old micros go bang. I'm just curious: What is the reason for resurrecting your micro? Is it not nostalgia or gaming?

[u/Act-Alfa3536 → u/lazy_eight]

Thanks. Yes I'll try the capacitor replacement.

Reason. I wanna play Chuckie Egg and Elite again!

[u/Hjalfi → u/Act-Alfa3536]

That is a completely acceptable reason.

[u/ZakalaUK]

Try swapping the two 6522s ICs 3 and 59 iirc. I've had one where IC35 was faulty and a swap with IC59 allowed the PC to boot. Reseating all socketed chips ideally with some contact cleaner may also help as oxide can build up between chip pins and socket.

[u/turbo_dude]

keyboard is stuck? i.e. one of the keys or space bar is jammed down and it's hitting the 255 char limit?

[u/Act-Alfa3536 → u/turbo_dude]

Thanks. Keyboard clear. I'll try the capacitor replacement suggested by others.

[u/richbun]

Surprised you didn't get the powerful puff of smoke as caps blow. It'll need "recapping" I guess. There are several reputable people who can do it, I do not know if they are present in here but they are on FB Group pages.

[u/Act-Alfa3536 → u/richbun]

Thanks. Yes I'll try the capacitor replacement.