Safety Modifications

Tweakers' Asylum

Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ.

I've got a couple of amps coming my way via eBay and before I rip out their guts and start working on them, I would like to get some advice on how I can make the amps safer:
1) How do I keep from getting horribly shocked by giant electrolytics that haven't discharged? What value resistors should I strap accross the filter capacitors? (for example 20mfd 600v = ?ohm ?watt)
2) What happens if a bunch of DC starts flowing throught the speaker interconnects? How do I install a fuse between the speaker terminals and the output transformers? (for example 20w @ 8 ohms = ?amp)
3) How can I check the bias in a push-pull configuration with inexpensive tools (i.e. a voltmeter)? How would I install a meter in the amp to display the bias when powered up?
4) Where would I put a standby switch to turn off the plate voltage while keeping the filaments warm? After the power transformer or after the filter section?
5) What else can I do to reduce the risk of damage to my health/speakers/tubes (in that order)?
Any help would be greatly appreciated. I'm working on two Heathkit W4's and a stereo amp to be named later (maybe Fisher X100).
Jackson West

Heathkit W4 Schematic (Open in New Window)

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Topic - Safety Modifications - jacksonwest 10:05:44 10/22/02 (5)

Re: Safety Modifications - jacksonwest 09:52:34 10/25/02 (0)

Re: Safety Modifications - 3moons 13:04:52 10/23/02 (0)

Re: Safety Modifications - SPARKS 13:23:05 10/22/02 (1)

Re: Safety Modifications - 3moons 12:59:50 10/23/02 (0)

OK here goes.... - Tiny Daddy 12:37:06 10/22/02 (0)

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