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Sansui G-5700 Clean/Recap

S

sonictrigger

New Member
Hi everyone,

I have this G-5700 which was sitting in my room at the family rural house (is a bit far from city) for a couple years, since I didn't have really enough space to put speakers and it on my room at the apartment. However, the room it was in was very humid, so looking back that was a bad move... But now I got some space and a pair of speakers, and would like to run this on my room.

It works okayish, needs to clean the pots, but the tunner is weird. I've noticed that once I power it on I can get the Quartz Locked really easy on a station, but after a few minutes it starts to be intermitent and doesn't settle. Also the display, has a few segments that power up when they shouldn't (last 2 pics in the imgur album, should be 102.1 and 103.0 respectively), and sometimes show a total random value (3rd pic from the bottom up)

A further look in I see theres rust and corrosion in a lot of places (I live in Rio de Janeiro, Brazil - so I'd blame the corrosive sea air for speeding up the process).

I've been making a list of the caps on the F-2980 board, dunno which other boards to recap or if I should just do them all... But from what I read on here, the power supply board would be the most prone to catastrophic failure, so I will do atleast that one.

Here's the list if anyone needs it, I think I got all the caps (don't trust the C# number tho, some were really hard to see or just corroded over) The items in dark yellow i have to check in the service manual, will update later

  • Sansui G-5700 F-2980
  • Capacity | Voltage Rating | C#
  • 3.3uF | 63V | C05
  • 3.3uF | 63V | C06
  • 3.3uF | 63V | C07
  • 3.3uF | 63V | C08
  • 1uF | 50V | C25
  • 220uF | 63V | C29
  • 100uF | 25V | C62
  • 100uF | 25V | C629
  • 1uF | 50V | C620
  • 220uF | 63V | C31?
  • 220uF | 63V | C32
  • 220uF | 63V | C30
  • 10uF | 16V | C617
  • 100uF | 63V | C60 NP (bipolar)
  • 1uF | 50V | C26
  • 220uF | 10V | C622
  • 10uF | 25V | C624
  • 470uF | 63V | C613
  • 470uF | 16V | C623
  • 33uF | 50V | C616
  • 1uF | 50V | C618
  • 1uF | 50V | C619
  • 220uF | 50V | C614
  • 33uF | 50V | C615
  • 100uF | 16V | C625
  • 1000uF| 63V | C612
  • 47uF | 63V | C611
Also this receiver had it's output blown (I don't know if it was only one or the two tho) back in 1990~ish.
Another thing with this receiver is the DC offset, the left channel stabilizes at around 10mV which from what I read is excellent, but the right channel keeps rising and stops at around 75-80mV (It raises from low like 5mv, is that normal?).


Imgur album with shots of the internals: http://imgur.com/a/op17J (warning: ~15x 5MB pics)

So yeah any suggestions/ideas are very welcome! I will be doing the lists of the caps in the following days, and updating this post as I go.
I gotta order it all at once since I'll probably be ordering thru Mouser, which charges $35USD alone for the shipping. Am also thinking about getting a kit of the Deoxit stuff, which includes the fader, gold and normal... for another 30+15$ Shipping. (not counting the 60% import duties on product price+shipping)

Cheers!

Edit: More boards caps list:


  • Sansui G-5700 F-3000 (LCD board)
  • Capacity | Voltage Rating | C#
  • 10uF | 16V | C01
  • 4.7uF | 25V | C05
  • 470uF | 16V | C18
  • 1uF | 50V | C31
  • 3.3uF | 16V | C04 BP
  • 1uF | 50V | C21
  • 4.7uF | 25V | C23
  • 33uF | 16V | C52
  • 1uF | 50V | C24
  • 1uF | 50V | C25
  • 3.3uF | 50V | C51
  • 33uF | 16V | C22
  • 33uF | 16V | C26
  • 3.3uF | 50V | C27
  • 33uF | 16V | C?#3
  • 1uf | 50V | C02

  • Sansui G-5700 F-2988 (tuner board)
  • Capacity | Voltage Rating | C#
  • 470uF | 16V | C79
  • 220uF | 16V | C72
  • 1uF | 50V | C16
  • 220uF | 16V | C69
  • 220uF | 16V | C?#4 (next to C69)
  • 3.3uF | 50V | C62
  • 4.7uF | 25V | C63
  • 1uF | 50V | C46
  • 3.3uF | 50V | C37
  • 3.3uF | 50V | C38
  • 3.3uF | 50V | C14
  • 1uF | 50V | C08
  • 3.3uF | 50V | C20
  • 1uF | 50V | C33
  • 1uF | 50V | C34
  • 100uF | 16V | C28
  • 0.22uF| 35V | C23 Tantalum
  • 1.5uF | 35V | C24 Tantalum
  • 3.3uF | 35V | C25 Tantalum
 
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Hello, and welcome to AudioKarma.

Yes, that looks pretty dirty. You can do some research here by reading threads about the G-X700 series. Google "site:audiokarma.org Sansui G-5700", or 6700 or 7700. There are descriptions of ways to carefully brush away some of the gunge, but you must be careful because these components have been there for 40 years.

I suggest that you read this sticky in the Tuner forum:
http://www.audiokarma.org/forums/index.php?threads/how-to-clean-a-tuner-analog.144163/

These are pics of my G-6700s F-2980 bd showing parts locations. Your G-5700 may not have all of these parts installed, and many may have different values, but the locations should be the same.





My schematic shows C615 as 33µƒ, 50V.

If you live in/near a large city I'd look for an electronics repair place and see if they carry deoxit, or know of a local source.

Good Luck - - -
 
ghazzer said:
Hello, and welcome to AudioKarma.

Yes, that looks pretty dirty. You can do some research here by reading threads about the G-X700 series. Google "site:audiokarma.org Sansui G-5700", or 6700 or 7700. There are descriptions of ways to carefully brush away some of the gunge, but you must be careful because these components have been there for 40 years.

I suggest that you read this sticky in the Tuner forum:
http://www.audiokarma.org/forums/index.php?threads/how-to-clean-a-tuner-analog.144163/

These are pics of my G-6700s F-2980 bd showing parts locations. Your G-5700 may not have all of these parts installed, and many may have different values, but the locations should be the same.





My schematic shows C615 as 33µƒ, 50V.

If you live in/near a large city I'd look for an electronics repair place and see if they carry deoxit, or know of a local source.

Good Luck - - -
Click to expand...
Thank you for the help! I can't see C615 value without taking board out, but it matches the color and size of another 33uF 50V so it must be that.
I got all the F2980 caps on a mouser list, all Panasonic FC except the big 8200UF ones, which I bumped the voltage from 63V to 80V, model is as follows: ECE-T1KA822EA (T-HA Series)


Also added in a 6.5536MHz crystal for the LCD board (F-3000), which I read somewhere that it is known for being a problem.

Now, I plugged in my headphones to listen to the receiver, and there's a loud hummm AND a FM radio on the right channel (moving the FM tuning does nothing). Left channel has just a hiss. I will see if I can record this tomorrow.

The tuner light was dead too, so I cut two pcb's and placed a nylon spacer for them on each side to mount a pair of LED's:
http://i.imgur.com/Blhm9k0.png
http://i.imgur.com/tLjORlE.png



- Just as I was replying, I gave another try to finding deoxit locally, and SURPRISE! Found one guy selling a "Deoxit Fader, the D-Series D100L Squeeze Tube, 100% solution, 2 ml" for 20$, waiting for his answer on the shipping cost to buy it!! One problem probably down -

cheers!
 
If you have applied power to the G-5700, I suggest that you record the value of the two rail voltages before you make any changes. The schematic shows that to be ±54vdc. Then compare that to readings after you replace the main filter caps.

It would also be wise to take a few other before/after readings, like the ±30vdc from the P/S.

If you have the time and the patience, you can check the operation of the receiver after each replacement. That is the best verification that the last replacement was OK. Just use your headphones, run an MP3 player into the AUX input, and keep the volume low.
 
Deoxit ordered, should arrive next week

The G-5700 powers on with no smokes, here's the before-recap values:
-54V reading: -57.8
+54V reading: +57.8
-30V reading: -30.72
+30V reading: +31.75
+40V reading: +43.9~44.0

Thanks again for all the help :beerchug:

Tomorrow I'll get the caps list of the tuner board & lcd board done

I recorded a bit of the humm: https://soundcloud.com/luciano-alberto/humm-sample (Note: I didn't have a stereo adapter so the humm came out on both channels, but it's only present on the right channel. It's also a bit quieter than in the recording)
 
More updates:
- Am taking more detailed pics and labeling each capacitor in the pic, updated main post list with corrections (also found 2 BP caps, C60 C626 (Thanks @ghazzer!) on F-2980 and C04 on F-3000)
- Deoxit arrived, after reading a tutorial here on AudioKarma that recommended using faderlube after cleaning, I'm stuck again. I only have the red one but the next point might be a solution
- Given the cost of the Caps on the power board alone, I decided to not have it shipped to brazil. Instead, I'll wait for the next time I travel (or a friend) to get it and thus avoid a hella higher costs = I can now buy more stuff, including the problematic MSM540 chip or an entire display board.
- Couldn't upload high res here on forums, so uploaded lower res pics, text is a bit blurry sorry
- Derp, just as I post this I realize I didn't post the tuner board & lcd caps list. Will edit them in the main post after this message is sent. (offtopic: I can now edit my other posts :D )

F-2980.JPG F-3000.JPG
 
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C626 on the F-2980 bd is a 100µƒ, 6.3v Bipolar cap. I don't see a C60. ?????

Your C?#1 is C623 - 470µƒ,16v
Your C?#2 is C613 - 470µƒ,63v.

If you are planning to replace the MSM5540 chip, you should get a 40 pin socket that it will fit, and solder that in instead of the chip.
 
Hi all!
So, it's been 3 years heh! But I'm finally back to this Sansui now that I've got a pair of YAMAHA NS-M40 to go in my desk and a parent is going to the US = can bring me components :banana:
I haven't posted here but will soon, I've modded a couple 1W leds (with a resistor to lower them) to replace the original lamp in 2016 :rolleyes:


I powered up the receiver today after these 2-3ish years, same status as before, a loww but noticeable FM on one of the channels... and a strange thing I noticed after half hour playing: the bass seemed to come and go, like suddenly the music would have all the low frequency cut from it, fiddling with the tone/bass control just remedied it but didn't come back 100%. I have to further test this.

So far I've thought about buying the following (trying to think in advance to certain issues like blowing up the output stage)
- Trimmer pots especially for the BIAS as I read they are prone to fail and can take out the channel
- Caps for the F-2980, F3000 and MAYBE F2988, certainly all the tantalums
- Main filter caps so I can do an A/B comparison between new and old.
- <strike>The damned MSM5540 IC</strike>Can't find it anywhere, except a local guy selling it for a whooping 150USD o_O
- Toshiba 2SA1962 and 2SC5242 from Digikey (per @EchoWars recommendation on another topic, albeit from 2006) to have as spares just incase


I will do some more testing next weekend possibly about the bass going out after some time, I was testing using my ceiling speakers and not the Yamaha's, so maybe it will be easier to notice on yamaha's. Also gotta check the output stage if they are stock or not, I remember my parents saying my grandpa replaced one of them or both sometime in the lifetime of the amp.



Again, thanks everyone for their help on this amp!

yours,
Luciano
 
Keep us posted on your progress.

A fine bristle brush (paint, or other) and a hair drier on cool setting will help with cleaning the dust off.

All components on the F2980 bd associated with the P/S are in the 600 series (C629, R612, etc). Other parts are for the main amp.

Did you ever find a "local" retail store where you can get some supplies?
 
Smallish update:
By luck found a M5540 chip avaiable here in Brazil for 45USD, bought it... let's see when it arrives.:rockon:

@ghazzer local retail store here mostly carry chinese stuff/capacitors, I can probably find some old-transistor for a premium price but no guarantee it's original :(

Finished the caps list on Digikey, just waiting to spot the problem on my G3000 (which I bought broken, started a thread to it) to see if I need more components for that one (also recapping that one entirely since there's not that many and to train to do the G5700 after)
 
sonictrigger said:
Smallish update:
By luck found a M5540 chip avaiable here in Brazil for 45USD, bought it... let's see when it arrives.:rockon:

@ghazzer local retail store here mostly carry chinese stuff/capacitors, I can probably find some old-transistor for a premium price but no guarantee it's original :(

Finished the caps list on Digikey, just waiting to spot the problem on my G3000 (which I bought broken, started a thread to it) to see if I need more components for that one (also recapping that one entirely since there's not that many and to train to do the G5700 after)
Click to expand...
Get a DIP40 socket for the MSM5540 chip so you do not have to touch it with a soldering iron, the are VERY VERY easily damaged with heat and ESD.
 
kevzep said:
Get a DIP40 socket for the MSM5540 chip so you do not have to touch it with a soldering iron, the are VERY VERY easily damaged with heat and ESD.
Click to expand...

Thanks! Almost forgot that one...
Found two types of sockets, one costing quite a bit more than the other (but still cheapish), which one would you recommend?
Screen Shot 2019-07-30 at 22.26.42.png
 
kevzep said:
Don't touch it unless you are grounded!! Put it in an Anti-static bag.....
Click to expand...

It arrived wrapped in bubble wrap, no anti-static o_O I hope it's fine
I've put it in an anti-static bag now


----

update:
Finished digikey order for both the G3000 and G5700 capacitors/parts/extras. Almost all capacitors are from Nichicon UFG series, except where I couldn't find the value I needed there.
A whooping 150$. Should be with me by the end of next week
https://www.digikey.com/short/pbf9jv if anyone is interested, I tried to put the references where I could fit them all in the Customer Reference tab
 
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Figured I'd use the opportunity of a family member in the US to get a couple more MSM5540 chips from CEITRON, incase the one I got is bad or for future receivers ;)
msm5540.jpg
Interesting it has the same datecode (or I'm reading it wrong), 6801 as the one I sourced here in Brazil hmm


Digikey wasn't delivered (Notice left - no secure location avaiable --- USPS), asked for a redeliver let's see how it goes

Yours,
Luciano
 
BLAH BLAH said:
:needpics:
Click to expand...

There's this old album from my first teardown of the receiver https://imgur.com/a/op17J
Here's two more outside pics with the led mod (full bridge rectifier from the AC supply to the old lamp with two 1W led at either side in series and a resistor + potentiometer to change brightness, mounted on a blank pcb with holes and screwed on the original clamp holes) g5700_1.jpg g5700_2.jpg

It's quite a job to get the receiver out :( I need to take some better pics of the internals
 
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