Armstrong 525 distortion on one channel

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Member
Joined 2010
Paid Member
If the resistor values are confusing, there are quite a few resistor band colour charts on the net and in parts catalogues and hobby mags. etc. Some charts are just a PITA to use, others are fun and help you memorise the coding so it becomes a simple, direct reading exercise. Try this one.

I'm puzzled that a resistor smoked even with a light globe in series with the power - and no glow at all? Perhaps a recheck of your wiring for this globe and a lower wattage bulb is in order (assuming you can find one). I have a few old plain 40 and 60W bulbs for this duty and they glimmer at the weakest of faults in amplifiers from 15-100W.

To be helpful, we need to know what parts you refer to, as asked before. So which part, if you can identify it from a PCB marking, from the schematc above or even the pics in the repair article, is the one that smoked? This could well be the result of refitting a part that has already failed or an error, short etc. in soldering.
 
Administrator
Joined 2007
Paid Member
Thanks for your help, I think I've completed all the instructions properly!

The 100w test bulb didn't light up when I turned it on, however some unknown resistor let out some smoke! Why do all the resistors i replaced all measure different values on each board? What setting should I be testing resistors on, 2000k, 200k, 20k, 2000 or 200?

If you are reading them in circuit they will all read strangly because of interaction with other parts. Also the slightest voltage (charge from caps) will upset most DVM's on resistance ranges.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.