View Full Version : TA7136 OPAMP Replacement in SX790


larryderouin
12-30-2010, 01:06 AM
Found out my 790 has bad OPAMPS (TA7136)x2 in the Tone Control Section. The TA 7136 is basically NLA as far as I can find. ANYWAY. I did find this interesting thread on DIYAUDIO, but it's really vague on how to do it. You replace the Single inline 7pin TA7136 with Dual inline 8 pin OPA604 or OPA2604. http://www.diyaudio.com/forums/parts/46179-replacement-ta7136p.html

My problem is I don't have the vaguest idea how to do this.

1.) Do I need a 2604 for each side(R&L) or just one?
2.) I know I'll need to socket this in and wire it in, but don't know how to figure out pinouts. (if it has more than 2 pins (+&-)) I'm lost!
3.) Which of the OPA 604 and 2604 would be a better match for the 7136?

If someone would be so kind as to look at the .pdf's attached, and match the pins for me I'd be very greatful. The TA7136.pdf is here: http://www.audiokarma.org/forums/attachment.php?attachmentid=245924&d=1292876900http://www.audiokarma.org/forums/attachment.php?attachmentid=245924&d=1292876900

Once I have the pinouts, I can make up the sockets and solder them in and install the chips. I just don't know how to figure out the electronic shorthand.



Thanks

Larry

skippy124
12-30-2010, 05:41 AM
Hi Larry

If of any interest, TA7136AP's are available locally here at approx $3 each, and I am happy to organise to send a couple to you ( I willl be ordering some other parts from the suplier early next week).

Cheers

John

markthefixer
12-30-2010, 06:49 AM
two dead chips means a very close look at the power going to the chips, too much voltage and blooie...

pins 4 and 7 iiac....

and these ta chips are running at a higher voltage than most op-amps can tolerate..

a primer on these things, i'll add to this post later when i have time to look at pin numbers on another computer - preventative anti-flooding measures are being implemented, 2 days of rain are beginning here with 8 to 12 inches of snowpack...

- power input
+ power input
(there is no ground going to the chip as "power")

output pin
minus input pin, also called the "feedback input" or inverting input
pos input pin also called the non-inverting input.

that's 5 pins

of 8 pins, if there are no "compensation" pins, that's just enough to squeeze a second amp into an 8 pin chip:


opa2604
4 - power
8 +power
1 output A pin
2 minus input A pin, also called the "feedback input" or inverting input
3 pos input A pin also called the non-inverting input.
7 output B pin
6 minus input B pin, also called the "feedback input" or inverting input
5 pos input B pin also called the non-inverting input.



each amplifier is a triangle, pointing right usually
the output comes from the right facing tip
the - and + INPUTS come in on the leftmost flat face
the + and - POWER comes in from the top and bottom, to the slanted sides of the triangle...

so this should now make sense:

i recently replaced the TA7136P in the phono section of a kenwood receiver. The difference is remarkable! wider sound stage and more detail.

I replaced two single op amps with 1 dual opamp. I had a OPA2604 on hand so I used that.

You could use:
NE 5532
OPA604 or OPA2604

Keep in mind that the TA7136P is in single in line package and the new parts come in DIP or even surface mount. So you will need to build a little pin-to-pin mapping or conversion.

TA7136P pins:
1. frequency comp
2. non-inverting input (+ input)
3. inverting input (- input)
4. V-
5. voltage comp
6. output
7. V+

So for modern op amps you probably don't need to map pins 1 and 5.

Good luck
Paba

he means to ignore pins 1 and 5 ...

and the ta7136b is drawn badly in the datasheet... i can see why you were confused...

mouser 595-OPA2604AP $4.75 ea

opa2603
1 left ta7136 pin 6 an output
2 left ta7136 pin 3 feedback input
3 left ta7136 pin 2 input
4 - power left or right ta7136 pin 4
5 right ta7136 pin 2 input
6 right ta7136 pin 3 feedback input
7 right ta7136 pin 6 an output
8 + power left or right ta7136 pin 7



edit: here's something interesting I have found, and am puttng it in here for posterity and future reference!!:

Brown Dog SIP adapter
browndogadapter
siptodipadapter
adapter

http://cimarrontechnology.com
http://cimarrontechnology.com/audioupgradeadapters.aspx

and other VERY useful stuff at very useful prices

Hyperion
12-30-2010, 07:13 AM
opa2603
1 left ta7136 pin 6 an output
2 left ta7136 pin 3 feedback input
3 left ta7136 pin 2 input
4 - power left or right ta7136 pin 4
5 right ta7136 pin 2 input
6 right ta7136 pin 3 feedback input
7 right ta7136 pin 6 an output
8 + power left or right ta7136 pin 7

Minor detail, but shouldn't this be opa2604

Also, check out Brown Dog (http://cimarrontechnology.com/) adapters by Cimmaron Technologies - who have pin for pin converters for this kind of upgrade.

larryderouin
12-30-2010, 11:59 AM
two dead chips means a very close look at the power going to the chips, too much voltage and blooie...

pins 4 and 7 iiac....

and these ta chips are running at a higher voltage than most op-amps can tolerate..

a primer on these things, i'll add to this post later when i have time to look at pin numbers on another computer - preventative anti-flooding measures are being implemented, 2 days of rain are beginning here with 8 to 12 inches of snowpack...

- power input
+ power input
(there is no ground going to the chip as "power")

output pin
minus input pin, also called the "feedback input" or inverting input
pos input pin also called the non-inverting input.

that's 5 pins

of 8 pins, if there are no "compensation" pins, that's just enough to squeeze a second amp into an 8 pin chip:


opa2604
4 - power
8 +power
1 output A pin
2 minus input A pin, also called the "feedback input" or inverting input
3 pos input A pin also called the non-inverting input.
7 output B pin
6 minus input B pin, also called the "feedback input" or inverting input
5 pos input B pin also called the non-inverting input.



each amplifier is a triangle, pointing right usually
the output comes from the right facing tip
the - and + INPUTS come in on the leftmost flat face
the + and - POWER comes in from the top and bottom, to the slanted sides of the triangle...

so this should now make sense:



he means to ignore pins 1 and 5 ...

and the ta7136b is drawn badly in the datasheet... i can see why you were confused...

mouser 595-OPA2604AP $4.75 ea

opa2603
1 left ta7136 pin 6 an output
2 left ta7136 pin 3 feedback input
3 left ta7136 pin 2 input
4 - power left or right ta7136 pin 4
5 right ta7136 pin 2 input
6 right ta7136 pin 3 feedback input
7 right ta7136 pin 6 an output
8 + power left or right ta7136 pin 7


Mark: The chips aren't dead, yet. This is directly related to the TONE CONTROL PROBLEM on the 790. All voltage checks are on that page. 2 concerns there, and they both have to do with PIN 1. (Voltage at the pin, and lack of 5p cap). I can follow where pin 7 is getting 21.5V from but have not been able to figure out where pin 1 gets 10.4V from(unless it's internal from the chip). If that's the case then the chip's both have a problem as the pin 1 voltage is about 1/2V less than pin7(currently 21V).

http://www.audiokarma.org/forums/showthread.php?t=339454

As I understand this. I would need 1 for 1 replacements. With the following pin changes.

2604 to 7136
1 / 6
2 / 3
3 / 2
4 / 4
5 / 2
6 / 3
7 / 6
8 / 7

PIns 2,3, & 6 would have 2 wires going to each and pins 4 & 7 1 wire ea. Pins 5 and 1 no wires.

Larry

larryderouin
12-30-2010, 12:11 PM
Skippy124, Thanks for the offer. I'm gonna go with another AK'er who's a bit closer to the East coast of the Colonies.

Mark: While driving around between Dr's appt's, it sank in. It's a good topic for a lesson plan, and it'll probably work good, (call it a wild hair) but I think I will stick with the TA7136P for now. Let's put it this way, I got a GODFATHER offer.

Thanks
Larry

markthefixer
12-30-2010, 06:58 PM
That was a 1 for 2 replacement, one opa2604 for TWO ta7136's....

As I understand this. I would need 1 for 1 replacements. With the following pin changes.

2604 to 7136
1 / pin 6 on first 7136
2 / pin 3 on first 7136
3 / pin 2 on first 7136
4 / 4
5 / pin 2 on second different 7136
6 / pin 3 on second different 7136
7 / pin 6 on second different 7136
8 / 7

PIns 2,3, & 6 would come from two DIFFERENT 7136's and pins 4 & 7 1 wire ea. Pins 5 and 1 no wires.

larryderouin
01-10-2011, 07:55 PM
PacificStereo offered 2 TA7136P1 chips for a GODFATHER price. Even Mother Nature couldn't screw with the mail this time (it snowed in SoCAL this week). They came thru 2 days after mailed (Coast to Coast) in great shape, installed and the 790 is makin Music:banana::music: like no tomorrow! Great Bass and Highs now. Lock to Lock on the controls is now seriously noticable.

Many thanks to All who offered ideas, part #'s, explanations, and the parts I finally purchased. Especially PacificStereo. Communication was great, he notified me when they shipped, and it arrived before I expected it to. :thmbsp::thmbsp:

Thanks!!!

Larry

The Gravity Enhanced Horizontally Challenged Middle aged Female of the species has exercised her vocal cords for the day! :hdphones: