Hi guys, thanks to diyaudio I solved a few problems in the past but I'm in to a new challenge now.
I use a denon DRA-825R for years now (at my computer), but since 1 year the treble setting don't work on one of the channels.
I opened it up once and I remembered that the double potentionmeter for the treble function had a different measurement on the bad channel.
I thougt: well it's only the potentionmeter and I don't use the treble EQ so, will do it in a few months. Yesterday it popped up in my mind and I would like to fix it.
The reason I started this topic was: I think it just simply is the potentionmeter, but... I measured it while still in place on the PCB (in circuit is what it is called I think?) I don't know if that is the way to measure it or that I measured the wrong things now (like something other is wrong in the treble EQ for that channel and that is the reason I got the values)
I use a denon DRA-825R for years now (at my computer), but since 1 year the treble setting don't work on one of the channels.
I opened it up once and I remembered that the double potentionmeter for the treble function had a different measurement on the bad channel.
I thougt: well it's only the potentionmeter and I don't use the treble EQ so, will do it in a few months. Yesterday it popped up in my mind and I would like to fix it.
The reason I started this topic was: I think it just simply is the potentionmeter, but... I measured it while still in place on the PCB (in circuit is what it is called I think?) I don't know if that is the way to measure it or that I measured the wrong things now (like something other is wrong in the treble EQ for that channel and that is the reason I got the values)
While measuring resistors in-circuit is tricky, there is one criterion that must always be satisfied (assuming power has been thoroughly drained to avoid misreadings): A resistor can never measure larger than its actual value. There might be other stuff in parallel that drags the reading down, but it could never go up.
What do you measure from one end of the pot to the other and from each end to tap on both the intact and the problematic channel? What is the nominal value?
What do you measure from one end of the pot to the other and from each end to tap on both the intact and the problematic channel? What is the nominal value?
As you have two "identical" channels, but one is "different", in-circuit measurements won't be the actual value but the *difference* may be a clue.
If it is a 10K pot and there is 5K across it, 3K is the expected value and 5K strongly suggests the pot is dead-open. Conversely 1K suggests Jon's idea that an "infinite Ohms" cap has gone low-Ohms.
One problem is: looking at left/right speakers and front/back (even inner/outer) pot sections, how do you know which is which, the good or the bad?
If it is a 10K pot and there is 5K across it, 3K is the expected value and 5K strongly suggests the pot is dead-open. Conversely 1K suggests Jon's idea that an "infinite Ohms" cap has gone low-Ohms.
One problem is: looking at left/right speakers and front/back (even inner/outer) pot sections, how do you know which is which, the good or the bad?
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