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9090DB Recap

That looks beautiful but all the electrician talk - as always - is like hieroglyphics to me! lol

I’m wondering... does anyone know an approximate (nothing crazy/unusual going on) price range for having a full recap and tuner alignment done at a shop?

Getting one of these today that the current owner says the only issue is intermittent channel drop on one channel.

I am hoping a good cleaning following the the DeOxit For Dummies thread might be all it needs but I’m too poor to not consider worst case scenario on this and I 100% am not capable (my hands definitely aren’t steady enough) of doing more than internal cleaning myself.
 
bubbajack80 said:
That looks beautiful but all the electrician talk - as always - is like hieroglyphics to me! lol

I’m wondering... does anyone know an approximate (nothing crazy/unusual going on) price range for having a full recap and tuner alignment done at a shop?

Getting one of these today that the current owner says the only issue is intermittent channel drop on one channel.

I am hoping a good cleaning following the the DeOxit For Dummies thread might be all it needs but I’m too poor to not consider worst case scenario on this and I 100% am not capable (my hands definitely aren’t steady enough) of doing more than internal cleaning myself.
Click to expand...
Can't talk money in these forums, but hope your switches just need cleaned. Pay "special" attention to the TAPE monitor switches. They are rarely used and will cause drop outs. Work it about 50 times with the power off, then try it. And of course other switches and pots too. After this, please start your own thread so there is no confusion.
 
First of all WELL DONE! Great pictures!

I have a 9090DB open on the bench right now and am doing a less through job on the recap. I have found these Bourns (Mouser #: 652-3306F-1-502) to be a great replacement for all horizontal trimmers. they drop into the 2.5mm/5mm lead spacing perfectly. They are single turn but for adjusting meters and such they are just fine and more stable than the original old parts.Notice the trimmers on this Dolby board.

IMG_20200801_131846245.jpg
 
MIJ_Pioneer said:
View attachment 1889010 View attachment 1889011 View attachment 1889012

Filter caps:

Kemet 13,000uf 100v - ALS70A133KE100
Ring Terminals: 165302
4.7k bleeder resistor: ERG-3SJ472A
* Screws and washers do not come with filter caps!

Not photoed:

F2654 Push Switch Circuit Board

Electrolytic Caps
C-07 10uF 16V E.C 2mm 647-UPW1H100MDD1TA 50v
Ceramic Caps
C-05 0.047uF 50V C.C 7mm 505-MKP2C024701C00JS 63v
C-06 0.047uF 50V C.C 7mm 505-MKP2C024701C00JS 63v

M704 Tune Meters Closure

Electrolytic Caps
C-0u 100uF 6.3V E.C 647-UPW1E101MED1TD 25v

F2623 Filter Circuit Board

Electrolytic Caps
C-05 2.2uF / Audio 50V E.C 5mm 505-MKS2-2.2/63/10A
C-06 2.2uF / Audio 50V E.C 5mm 505-MKS2-2.2/63/10A

Bias setting * Note the schematic is wrong for the bias pots to trim. Also I was getting slightly diffrent readings in mA when a fuse with either in or not in on the other channel not being biased. I stuck with the manual at the end and left the fuse in the other channel during final adjustment (I knew I was in the ballpark of a few mA).

View attachment 1889016 View attachment 1889018

BOM I used,

Here is how I bypassed the Dolby board:

View attachment 1889017






And here she is getting her first session of playing! Installed ice blue LEDs and wired the tuning needle to be on at all times.

View attachment 1889019 View attachment 1889020 View attachment 1889021 View attachment 1889022
Click to expand...

Excellent work! I have a 9090db that I will be replacing the LEDs on today. Do you recall how you wired the tuning needle to be on all the time? Any pics of that?

I would love to recap, resistor, etc mine but the only boards I have worked on was when I built a few guitar pedals. Would you say this is a project that someone could tackle as long as they can solder and then replace the pieces exactly how they came off the boards? I see the kits on eBay, but I am thinking to myself...this can't be as easy as a paint by number so to speak. Thanks!
 
MIJ_Pioneer said:
View attachment 1889010 View attachment 1889011 View attachment 1889012



Bias setting * Note the schematic is wrong for the bias pots to trim. Also I was getting slightly diffrent readings in mA when a fuse with either in or not in on the other channel not being biased. I stuck with the manual at the end and left the fuse in the other channel during final adjustment (I knew I was in the ballpark of a few mA).
Click to expand...
That is because you have the STV-3H BIAS Diode version of the driver board. The SM is for the earlier 2SC984 BIAS transistor version where the BIAS pots do turn the opposite way. Also the value of the BIAS pots is different between the two.
 
slowvinyl said:
Excellent work! I have a 9090db that I will be replacing the LEDs on today. Do you recall how you wired the tuning needle to be on all the time? Any pics of that?

I would love to recap, resistor, etc mine but the only boards I have worked on was when I built a few guitar pedals. Would you say this is a project that someone could tackle as long as they can solder and then replace the pieces exactly how they came off the boards? I see the kits on eBay, but I am thinking to myself...this can't be as easy as a paint by number so to speak. Thanks!
Click to expand...

Thank you. I think you would do just fine as long as you had some practice and the right tools. You may want to consider getting a cheaper piece of gear to start on. I first started on an affordable model, and my next project was an expensive Pioneer SX-1280. While I was able to perform the recap I had to revist it many times as I learned that I missed things.

For the tuning needle I probed the voltages of the lamp when it was on/off. I moved one wire to a constant voltage (which I do not recall what that was) at a nearby pad.

Skywatcher said:
That is because you have the STV-3H BIAS Diode version of the driver board. The SM is for the earlier 2SC984 BIAS transistor version where the BIAS pots do turn the opposite way. Also the value of the BIAS pots is different between the two.
Click to expand...

That makes sense!
 
Updating this thread with better photos for bypassing the Dolby Board, I've been asked a few times:

1/ Here is the Dolby board untouched. Circled below are the signals going into the Dolby board.

index.php


2/ Cut the below traces very carefully.

index.php


3/ Solder the L / R wires from Step 1 as indicated below

index.php


4/ The finished product should look similar to below

index.php


That's it, after that enjoy your bypassed Dolby Board. Note you will lose Tape 1 and Tape 2 functions.
 
MIJ

Thank you for the quick response and your descriptions and photos explain the modification very well. My 9090db is still working perfectly but it is s relief to know if the db board goes south there is a fix that can easily be done. I will never miss the tape 1 and 2 functions. You did a great job figuring out the db board work around.
Thanks again
Charlie
 
I have a 9090 in for service now. Just came in Monday evening. Should have it on the bench today some time,... if I can get the Akai AA-1050 finished (it's being very cantankerous). Glad it's not the 9090DB. I have done only one of those and the customer didn't want Dolby bypassed. Geez, what a meticulous job! BTW,... nice job on the bypass!
 
MIJ_Pioneer said:
View attachment 1888959 View attachment 1888960 View attachment 1888961 View attachment 1888962 View attachment 1888963 View attachment 1888964


F2624 Driver Circuit Board

* I did not replace any transistors. Can always come back and revisit. TR01 - 04 are matched C1400. I compared the HFE to a 1845 and the 1845 has half the hfe. I put the original back in.

Electrolytic Caps
C-01 0.47 50V E.C 2mm / Low Noise 505-MKS20.47/63/5 63v
C-02 0.47 50V E.C 2mm / Low Noise 505-MKS20.47/63/5 63v
C-05 470uF/16V/5LS 6.3V E.C 4mm 647-UPW1V471MPD 35v
C-06 470uF/16V/5LS 6.3V E.C 4mm 647-UPW1V471MPD 35v
C-07 330uF/100V/7.5LS 63V E.C 7mm 647-UPW2A331MHD 100v
C-08 330uF/100V/7.5LS 63V E.C 7mm 647-UPW2A331MHD 100v
C-09 100uF/50V/5LS 25V E.C 4mm 647-UPW1J101MPD6 63v
C-10 100uF/50V/5LS 25V E.C 4mm 647-UPW1J101MPD6 63v

VR1: 4.7k Ohm: 652-3296P-1-502LF 5K Ohm Multi Turn
VR2: 4.7k Ohm: 652-3296P-1-502LF 5K Ohm Multi Turn
VR3: 100 Ohm: 652-3386H-1-101LF 100 Ohm Single Turn
VR4: 100 Ohm: 652-3386H-1-101LF 100 Ohm Single Turn

Diodes
D-05 340120 VD1212 2 X 512-1N4148 in series Fairchild 2 X 1N4148
D-06 340120 VD1212 2 X 512-1N4148 in series
ZD-01 316070 EQA01-24R 512-1N5252B Fairchild 1N5252B
ZD-02 316070 EQA01-24R

R-33 180 ohm Fuse R. 594-MBB02070C1800FCT
R-34 180 ohm Fuse R. 594-MBB02070C1800FCT
R-35 4.7 ohm Fuse R. 594-MBB02070C4708FCT
R-36 4.7 ohm Fuse R. 594-MBB02070C4708FCT
R-39 10ohm Fuse R. 594-MBB02070C1009FCT
R-40 10 ohm Fuse R. 594-MBB02070C1009FCT
R-41 150 ohm Fuse R. 594-MBB02070C1500FCT
R-42 150 ohm Fuse R. 594-MBB02070C1500FCT
R-43 150 ohm Fuse R. 594-MBB02070C1500FCT
R-44 150 ohm Fuse R. 594-MBB02070C1500FCT
R-47 4.7 ohm Fuse R. 594-MBB02070C4708FCT
R-48 4.7 ohm Fuse R. 594-MBB02070C4708FCT
R-49 4.7 ohm Fuse R. 594-MBB02070C4708FCT
R-50 4.7 ohm Fuse R. 594-MBB02070C4708FCT
R36: 4.7 Ohm 1/4 watt: 660-MF1/2DCT52R4R75F 4.75 Ohm 1/2 watt 594-MBB02070C4708FCT
R37: 3.9k Ohm 1/2 watt: 660-MF1/2DCT52R3921F 3.92k Ohm 1/2 watt 594-MBB02070C3901FC1
Click to expand...
I think you might of put the wrong part for:
C-05 470uF/16V/5LS 6.3V E.C 4mm 647-UPW1V471MPD 35v
C-06 470uF/16V/5LS 6.3V E.C 4mm 647-UPW1V471MPD 35v

Shouldn't those be UKL or UES?
 
With this topic, that includes bypassing the db board on a Sansui 9090db, a potential purchaser and all 9090db owners will not have to worry about having a non working receiver, since failed db board 9090db can be fixed by by passing the db board and still serve as a great working receiver. Now, many that think the 9090db is to be avoided can reconsider that choice unless they just have to have a 9090db in perfect condition, for as long as that will last.

My 9090db has a good working db board now and I can now sleep easy knowing if it fails I can now easily bypass the bad db board.

Thanks MIJ Pioneer again for doing this for all 9090db owners.

Charlie
 
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MIJ_Pioneer said:
In some aspect I had to build this list from information across many threads. There was no one clean recap list - from my searching the trimmers other than the driver board never came up and therefore overlooked. Other than the Dolby board and the Dolby FM trimmers near the tuning gang, the is the one for regulating the RF board voltage and the tuning meters right? Going off memory here.
Click to expand...
Very well posted thread.
I have a 990DB on the bench that has the right channel blown out. I'm referencing your thread.
It was at a yard sale in the back of the garage. The gentleman asked if I was looking for anything particular. I said that 990DB. He said its not for sale, it was is Aunt's, besides its broken. "I can fix it!" I said.
So its here, and I wish I talked them out of it. Absolutely fantastic receiver.
Anyway, great thread.
It takes us "Pioneer guys" to help organize the other forums. ;)
 
Well, at least Zebulon you now can rest easy that there is no easy bake power supply on our wonderful 9090db that will cook your fingers like the SX1010 :)
but be warned spending quality time with the Sansui gear might just convince you to hang out with us for a while.
 
Thank you very much for this comprehensive workup. I see others here with you on the topic as well which i fimd useful.
On the BOM list, can you help supply one for the driver board specifically please? I do have the later one in the unit im working on, but also have 9 other 8080/9090db snd 3 9001 so am going to need to understand both versions, besides just the VR.
I see what says BOM list towards the beginning, but it doesn't seem to be a downloadable file i can import into digikey. I must be doing something wrong i suppose.
I plan to do these driver boards first, get the unit working (found bad bias resistors and a transistor with help from other threads). Hence the driver board bom. I then intend to move to the rest of the unit as outlined here once its repaired, so a full bom list. Not sure if i can seperate a full list or import partial list to accommodate.
I see kits for the amp board for 40 plus tax and shipping which i would like to avoid by buying the parts this way. Given how many units i have.
Thank you very much for your detailed postings.
 
allhartfidelity said:
I see what says BOM list towards the beginning, but it doesn't seem to be a downloadable file i can import into digikey. I must be doing something wrong i suppose.
Click to expand...
Please bear in mind that at least some of the components on a BOM only a month or two old may be NLA, so you might have to manually select and order substitutes. I ordered some parts a few weeks ago and was shocked at how many were no longer available, having said that Digikey seems to be holding up a bit better than Mouser, good luck!
 
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