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G-9000db - it's OCCRD recap time!

w1jim

w1jim

I can fix it but good...
Subscriber
I knew this day would come - when I finally got around to recapping my G-9000db.
It started sounding scratchy - all it probably needs is a good switch cleaning and some new speaker relays but I figure anything worth doing is worth overdoing. It's a known symptom of my OCCRD (Obsessive Compulsive Capacitor Replacement Disorder).

This receiver looks to have had a gentle life - there are no signs of heat damage on any of the PCBs so I don't think I'll need to replace any of the power resistors.

I'll be replacing all electrolytics except for the big oval power supply caps. All electrolytics 1uf or less get replaced with poly films. All tantalums (if there are any) will also get replaced with electrolytics or poly films.
The bulk of the replacements will be with Nichicons.

Yesterday I opened the top and bottom and got some parts I don't have on hand ordered - basically the 2 Omron speaker relays and a couple of larger caps. Everything else I should have on hand here.

Today I did the 2 amplifier driver boards. The larger caps were a bit smaller in diameter so I used some heatshrink tubing to enlarge them slightly to fit in the clips.

F-2806 amplifier driver boards (2):

4 - 470uf/80v
4 - 33uf/25v
2 - 1uf/50v BiPolar (replaced with a poly film)



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Off to a good start there..........I did this to my G-9K recently too......
Are you going to replace those 1/4watt fusible resistors with some nice new metal films?
This probably sounds really anal, but I went through and replaced all the resistors with 1% metal films.......
Thats probably overkill but it would be a good idea to replace at least the fusible resistors, they are the 1/4 watters with the little S bend in the legs.....they do randomly fail, so I think its a good preventative measure to take.....
 
I'll have to think about those incendiary resistors - are they all 1/4 watts? There seem to be some larger ones with the "S" bends to them.
Yes, replacing all of the resistors could be considered extreme (even by my standards).

What did you do for the 220uf/6.3v and 4.7uf/80v bipolars? Seem like odd sizes - the high voltage on the one and low voltage high capacitance on the other are a challenge, especially given the space limitations.
I was of either leaving them alone or creating bipolars out of 2 polars.
Thoughts?
JimB
 
Found the bipolars at Mouser.com:
220uf/6.3v (these are 10 volts) - 647-UVP1A221MPD
47uf/80v (these are 100 volts) - 647-UVP2A4R7MED

Any other bipolars you know of hiding in there?
 
Head amp

Recapped most of the F-2796 "Head Amp".
Two caps are still to be replaced (on order).

F-2796 Head Amp:
4 - 470uf/35v
4 - 47uf/50v
2 - 210uf/16v
2 - 220uf/6.3v bipolar



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this one's a bit of a PITA to access - I removed the red wire that goes to the tuner to gain access.

F-2810 Tuner Power Supply:
1 - 4.7uf/50v
1 - 100uf/10v
1 - 220uf/16v
1 - 220uf/50v
1 - 1000uf/50v


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w1jim said:
I'll have to think about those incendiary resistors - are they all 1/4 watts? There seem to be some larger ones with the "S" bends to them.
Yes, replacing all of the resistors could be considered extreme (even by my standards).

What did you do for the 220uf/6.3v and 4.7uf/80v bipolars? Seem like odd sizes - the high voltage on the one and low voltage high capacitance on the other are a challenge, especially given the space limitations.
I was of either leaving them alone or creating bipolars out of 2 polars.
Thoughts?
JimB
Click to expand...

You know, I think I left those Bi-polars, I came to the same conclusions, the values arent conducive to an easy alternative.....I tried to find those values but it proved to be very difficult.....I really wanted to have a clean sweep but it just wasnt going to happen..........
I might actually go back and see if I can track some down........

The fusible resistor situation is a difficult one, I have had people tell me there are only 1/4watt, some say 1/4 and 1/2watt......this is what lead me to do the whole lot......there is a lot of critical current flow on this board and those larger 3watt resistors get quite hot as you can see from the board, so I figure the years of thermal cycling at some point will end the life of these resistors......so replace them I did......
Use metal film always, because metal film is non inductive, and mount them off the board.........
 
bbauer01 said:
Do you ever stop and take a breather? :) Nice work so far...
Click to expand...
Just trying to put the "BIG O" back in obsessive. Started on the G22K yet :banana:?

F2807 & F2808 Power Supply boards:
2 - 1000uf/80v
1 - 2200uf/16v


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Impetus to start this was because I had to order some transistors for an AU-9500 I'm fixing for another AKer - figured I might as well bulk up the order with some parts for this.
Also I noticed there wasn't a cap list for this so really it's just a public service.
Working on the main PS board now and then time to pull the faceplate.
 
Nice work!!

w1jim said:
It's a known symptom of my OCCRD (Obsessive Compulsive Capacitor Replacement Disorder).
Click to expand...

Preaching to the choir here!!! Whenever I acquire a desirable new amp (even if it is still in transit) I'm extremely quick to source the service manual and schematics, and I quickly draw up a bill of materials and save an order on the website of my chosen electronics supplier so that I'm ready to go! ;)
 
pete_mac said:
Nice work!!
Preaching to the choir here!!! Whenever I acquire a desirable new amp (even if it is still in transit) I'm extremely quick to source the service manual and schematics, and I quickly draw up a bill of materials and save an order on the website of my chosen electronics supplier so that I'm ready to go! ;)
Click to expand...

I am the same way... that and browsing threads of others to find pics and details on problem areas. Then I save all the links in a folder and created a spread sheet with a materials list and things to watch out for based on the experiences of others. As I progress with the project I save my notes with the rest of the info. It works out very nice and has helped me answer a few questions.

w1jim said:
Just trying to put the "BIG O" back in obsessive. Started on the G22K yet :banana:?
Click to expand...

You are worse than me...

Not yet on the G-22k recap. I have two SG-9800s to finish. ...was trying to buy a G-33k. I must be on some kinda spendin' spree. The G-22k will be recapped soon... sooner than the D7000 based on its condition.

Sorry to crap your thread.

Now back to W1jim's regularly schedule (recap) programming...
 
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pete_mac said:
Nice work!!



Preaching to the choir here!!! Whenever I acquire a desirable new amp (even if it is still in transit) I'm extremely quick to source the service manual and schematics, and I quickly draw up a bill of materials and save an order on the website of my chosen electronics supplier so that I'm ready to go! ;)
Click to expand...

Well in the case of the G-9000 service manual, there isnt a complete component list to work from.....
I had to go through and actually manually compose a list........
But it doesnt take too long in any case....
All good though, Jim is ripping into it.......
 
kevzep said:
Well in the case of the G-9000 service manual, there isnt a complete component list to work from.....
I had to go through and actually manually compose a list........
But it doesnt take too long in any case....
All good though, Jim is ripping into it.......
Click to expand...

That and sometimes the values of resistors and caps on the board don't match the SM...
 
kevzep said:
Well in the case of the G-9000 service manual, there isnt a complete component list to work from.....
I had to go through and actually manually compose a list........
But it doesnt take too long in any case....
Click to expand...

Same goes for most of the Sansui's that I've done... they seem to refer to the 'Sansui Common Parts List' for the standard, commonly-used caps.

I either refer to this list in conjunction with the limited info in the service manual, or just create a list directly from the schematic and verify the list against the parts actually fitted on the boards :)
 
Nice work... I'll be following this thread, as I would love to get a list of replacement caps so I can have someone recap mine. :)
 
Yeah, I've been keeping busy.
Some weird parts in here - a bunch of 100uf/6.3v & 4.7uf/80v bipolars, 3.3uf/63v electrolytics and .068uf/35v tantalums in the phono section - (those last ones are staying).
Now just waiting for the Mouser truck to pull up to the front door.




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Wow, thats about as "in bits" as it gets...........

Yes there are some unusual values in there alright..........

Are you replacing the "tantrums" with something else.......we dont like it when tantalum's have tantrums!!!!!:D

Have you given some thought to the Ovals?? I remember you said you were going to leave them.....would be a shame to come this far and not consider it......
Ive been thinking about mine, but thats as far as Ive got so I cant preach.....
 
Tantalums get replaced with electrolytics except values 1.0uf and less which get poly film caps.
Those .068uf (aka 683) - I'll see if I can find some poly films locally or maybe from my parts pile.
The ovals - nope, they're going to stay. Are those bad boyz even available? If I did decide to replace them later (unlikely) they wouldn't be very hard to get to, relatively speaking.
I've got all but 12 caps replaced on the underside and I've already pulled the relays - then it's time to do the tuner.
 
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