Every servicable relay replacement from the 80's era has been in vain IMO, leave em.
Denon POA 6600 Thread
- Thread starter Bratwurst7s
- Start date
I was looking at those POA 6600 mono block specs just now. F'in beasts! Do power supply bypass caps sweeten up the upper range or something? Curious.
Strongly agree. Wink, wink, nod, nod.
zaibatsu has good knowledge and is always a pleasure to have around in a thread.
,James
Maybe he'll show up more if we drink less beer and don't fart so much...Strongly agree. Wink, wink, nod, nod.
zaibatsu has good knowledge and is always a pleasure to have around in a thread.
James
We stink
I came to the same conclusion a few minutes ago and just re-installed the speaker terminal block with the old relays in place. If there proves to be a problem I have 10 of those replacements and they are pretty easy to get to.
James
My experience with working the PSU in CDP's was that it simply made the overall sound a bit cleaner and more "open".
If the contacts are smooth on a heavily used piece I just work a burnishing tool across the contacts a little. Hardest part is getting the damn relay cap off sometimes. I try and stay under 2 beers for relay ops.I came to the same conclusion a few minutes ago and just re-installed the speaker terminal block with the old relays in place. If there proves to be a problem I have 10 of those replacements and they are pretty easy to get to.
James
Pointy contacts kinda suck over time.
It's easy to see that the heat sink is an integral structural member. It supplies the major part of stability between the front and rear panels.
All back together now except for the amp board. Now that tan go up on the shelf all ready while I concentrate on the board.
,
James
All back together now except for the amp board. Now that tan go up on the shelf all ready while I concentrate on the board.
,James
My favorite burnishing tool is piece a match box cover and some alcohol. Not the drinking type. High Tech.If the contacts are smooth on a heavily used piece I just work a burnishing tool across the contacts a little. Hardest part is getting the damn relay cap off sometimes. I try and stay under 2 beers for relay ops.
Pointy contacts kinda suck over time.
,James
Nice... Did you order up replacement main filter caps or no...They're skinny and probably dry as a popcorn fart within. Fat caps hold the electrolytic sauce longer IMO.
Either way, that amp is straight up porn. Nothing I own has a torroidal transformer. F
Either way, that amp is straight up porn. Nothing I own has a torroidal transformer. F
Added that one to the book of esoteric redneckisms, thank you sir. De-ox won't hurt the contacts either.
Not so sure. I will use deoxit when cleaning/polishing but I don't like to leave any kind of residue on a contact that can burn under an arc.
I am leaving for Arizona in 13 days. All orders are on pause until the middle of May.
Yeah, it is a massive chubby producing heavy transformer. You have no idea how much I am looking forward to getting 2 of these things in the system. My speakers have responded well to each increase in power. The little MA500's are nice but severely limited by the brutal load that I am putting the poor things through. Kinda like your cat. I hope that it lives after getting that shot of poison gas.
,James
I like cats but living on the 9th (US count) floor in a 900²f apartment is a no go with pets now.
It was a long and stressful project to teach our cat back in the US to stay away from the music system. She never really liked me all that much after that, but we got along.
This is our cat these days.
The perfect audio cat:
Fake, flat, doesn't shed hair or claw speakers and doesn't need a catbox.
The only kind of cat that is allowed to sleep on my speaker.
,
James
The perfect audio cat:
Fake, flat, doesn't shed hair or claw speakers and doesn't need a catbox.
The only kind of cat that is allowed to sleep on my speaker.
,James
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That and guard your beer. Except, that IPS stuff tastes like crap to me.
Gonna go over with an empty suitcase and come back with a bunch of Wrangler jeans. They cost something like €100 here.
Popped my Top a little early today, but what the heck, I don't have to work tomorrow. Or ever again for that matter.
So, to do a small review here.
This amp is actually the first one that I unpacked. It went on the bench, passed the dim bulb test, was opened, put on the mains and the idle current was adjusted after 10 minutes to the stated 8mV.
Later, when I was having problems with the second amp I put this one back on the bench with the intention of taking a great many voltage measurements and comparing them to the misbehaving amp to get a better picture of where that amp was having problems. It warmed up about 20 minutes on the bench after opening it up.
I was sitting there looking at the schematic deciding where to start and just like that R536 flashed, burned and smoked. This is a 1k ohm fusible. The trace from one end of that part runs to R562 (47 ohm fusible) and then to the output trace that all of the output transistors feed into.
The other end of R536 goes to the junction of C520 (33pF) and pin 2 of IC501 (NJM082BD).
Something pulled a lot of current through that resistor.
It has just now been replaced with a Vishay RN60 1k part.
Next I pulled R562. Being only a 47 ohm fusible I would guess that it would have burned first if there was a shorted transistor etc on that end of the trace. It tested at 46.5 ohms. Now replaced with a RN60 47 ohm.
Next I went back in the other direction and pulled C520. It tested at 32pF. Replaced with a TDK MLCC C0G part.
Lastly for today I pulled IC501 and replaced it with a socket.
I still don't know how to bench test an op-amp.
That's it for today, the new Mark Knopfler CD arrived in the post today and now it's time to check that out.
,
James
This amp is actually the first one that I unpacked. It went on the bench, passed the dim bulb test, was opened, put on the mains and the idle current was adjusted after 10 minutes to the stated 8mV.
Later, when I was having problems with the second amp I put this one back on the bench with the intention of taking a great many voltage measurements and comparing them to the misbehaving amp to get a better picture of where that amp was having problems. It warmed up about 20 minutes on the bench after opening it up.
I was sitting there looking at the schematic deciding where to start and just like that R536 flashed, burned and smoked. This is a 1k ohm fusible. The trace from one end of that part runs to R562 (47 ohm fusible) and then to the output trace that all of the output transistors feed into.
The other end of R536 goes to the junction of C520 (33pF) and pin 2 of IC501 (NJM082BD).
Something pulled a lot of current through that resistor.
It has just now been replaced with a Vishay RN60 1k part.
Next I pulled R562. Being only a 47 ohm fusible I would guess that it would have burned first if there was a shorted transistor etc on that end of the trace. It tested at 46.5 ohms. Now replaced with a RN60 47 ohm.
Next I went back in the other direction and pulled C520. It tested at 32pF. Replaced with a TDK MLCC C0G part.
Lastly for today I pulled IC501 and replaced it with a socket.
I still don't know how to bench test an op-amp.
That's it for today, the new Mark Knopfler CD arrived in the post today and now it's time to check that out.
,James
Made a bit of progress today and checked everything in and around the idle current section all the way over to the edge of the voltage amp section. Also tested and sorted matched sets of 5 each of KSA1381 and KSC3503 to get ready for the voltage amp section.
The 2 14.8v zeners (D506, 507) tested low at about 14.4v, found a pair of new ones that tested at 14.75v.
Everything else checked very nominal.
Fusible resistors were replaced with 1/4w Vishay RN60, the rest with SFR25 except for the 4 1w MOX, those were re-installed.
Caramic caps and a couple of mylar were replaced with MLCC C0G.
C518 and 519, 220µF/25v were replaced with Panasonic FM 35v.
Tomorrow I'll start looking through the voltage amp section.
,
James
The 2 14.8v zeners (D506, 507) tested low at about 14.4v, found a pair of new ones that tested at 14.75v.
Everything else checked very nominal.
Fusible resistors were replaced with 1/4w Vishay RN60, the rest with SFR25 except for the 4 1w MOX, those were re-installed.
Caramic caps and a couple of mylar were replaced with MLCC C0G.
C518 and 519, 220µF/25v were replaced with Panasonic FM 35v.
Tomorrow I'll start looking through the voltage amp section.
,James