The best way to power up post recap

jmcturnan

New Member
Hi, i just finished a significant recap of my Onkyo TX-8500. All boards were redone. I did test after the power board, amps before i did the preamp and phono boards .

I have a dim bulb tester. What is the safest procedure to do a first test? Disconnect amp boards?

Many thanks!
 
DBT + power-on the unit is OK if you trust your work.

If you don't trust what you did, check again the part you don't trust 100%.
 
I go over all of my work with a magnifier AFTER letting it sit overnight. I get tired eyeballs after hours of soldering and seem to make stupid mistakes if I keep pushing (especially if the hours of soldering are following a 9-10 hour day of regular work).
After giving it a good once over I'll use a DBT and go for it.
 
I hook a couple of meters up to measure the bias before powering up with a DBT. If it's too far out of adjustment it'll light the bulb up just like there's a short.
 
I hook a couple of meters up to measure the bias before powering up with a DBT. If it's too far out of adjustment it'll light the bulb up just like there's a short.
I do the same when replacing transistors, I expect a lower bias current with the DBT, near half of the specs if the bulb is not too large.
 
Not a bad idea to run the bias trimmers through their expected range a few time while monitoring your meters. You want to look for spikes in the voltage or current. This is especially critical if you haven’t replaced the trim pots. The DBT will probably save you if one of them has a bad spot.
 
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