The op-amps on the board are the black 8-pin components.
You need to replace it. I'd recommend using an exact replacement. If you want a temporary replacement, you can probably get a TL082 from Radio Shack.
You need to replace it. I'd recommend using an exact replacement. If you want a temporary replacement, you can probably get a TL082 from Radio Shack.
These op-amps have (Malaysia C4570C 8847R) stamped on them. I have found several online but there are a lot of different manufactures. Who should I source them from?_
And If this is the fix(fingers crossed). What else can I do internally while its appart to improve this amplifier?_ I'm not looking for more power, I'm talking about "Reliability Upgrades"
It may take a few days to get the parts. I will replace and let you know. Thank you so much for your help.
And If this is the fix(fingers crossed). What else can I do internally while its appart to improve this amplifier?_ I'm not looking for more power, I'm talking about "Reliability Upgrades"
It may take a few days to get the parts. I will replace and let you know. Thank you so much for your help.
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You can buy 2 of them but, at this point, you only need to replace the one nearest the RCA jacks.
I didn't see the earlier post.
The originals seem to be in short supply. The TL082s will work and are typically not finicky. Others may try to talk you into some 'high-performance' op-amps but those can cause all sorts of problems without modifying the circuit.
I'd leave the amp as-is. If you use proper fusing (30 amps per power wire), if something goes wrong, the fuse should limit the damage.
The originals seem to be in short supply. The TL082s will work and are typically not finicky. Others may try to talk you into some 'high-performance' op-amps but those can cause all sorts of problems without modifying the circuit.
I'd leave the amp as-is. If you use proper fusing (30 amps per power wire), if something goes wrong, the fuse should limit the damage.
When you say "high-performance op-amps can cause all sorts of problems without modifying the circuit" does that apply to this one?
C4570C Ultra-Low Noise, Wideband Dual Op Amp
$0.35
C4570C
The C4570C is an ultra low-noise, wideband high slew-rate, dual operational amplifier.
The C4570C is an excellent choice for pre-amplifiers and active filters in audio, instrumentation, and communication circuits.
MFG: NEC
Info Here: C4570C Datasheet catalog
Add to Cart:
C4570C Ultra-Low Noise, Wideband Dual Op Amp
$0.35
C4570C
The C4570C is an ultra low-noise, wideband high slew-rate, dual operational amplifier.
The C4570C is an excellent choice for pre-amplifiers and active filters in audio, instrumentation, and communication circuits.
MFG: NEC
Info Here: C4570C Datasheet catalog
Add to Cart:
- Model: 180-1023
- Shipping Weight: 0.001lbs
- 2405 Units in Stock
You found the original part so your doing Ok.
Perry was referring to Burr-Brown, and AD , and National Semi, Super Op-amps. They are as their name implies Super op-amps and they can cause all sorts of issues when being used in a lessor design due to their very wide bandwidth and gain characteristics. As I said you have found the original parts so your doing AOK...🙂
Perry was referring to Burr-Brown, and AD , and National Semi, Super Op-amps. They are as their name implies Super op-amps and they can cause all sorts of issues when being used in a lessor design due to their very wide bandwidth and gain characteristics. As I said you have found the original parts so your doing AOK...🙂
They are the same. One was made in the 47th week of 1988. The other was made in the 12th week of 1988.
Thanks, Installing now. I Will not have my car here today to test with audio signal. I can test with battery and headlight. What should I be looking for on pins 1,2, and 3 with to imputs connected?_ The last test showed zero on all 3 pins leading to the op-amp replacement. I'll post results later today.
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You will need a signal source to test it. The 0v DC was OK. The problem was that you had signal on pin 3 but had no output from pin 1.
Ok, I will test this evening with signal. Op-amp is installed and waiting for test vehical. Thanks again
I have sound!!!! I replaced the op-amp closest to the RCA's and with 1v supplied through the RCA's I get 1v on Pin#1 on both op-amps. On Pin#7 I get .3 on both op-amps. When subs are hooked up the left rca sounds great the right channel is about 1/3rd the volume. So there is an improvement (Sound)Thank you,Thank you,Thank you.
Does the .3v on pin7 of both boards have anything to do with me getting 1/3 the sound out of the previously dead channel that is now working?_
Does the .3v on pin7 of both boards have anything to do with me getting 1/3 the sound out of the previously dead channel that is now working?_
Yes, I actually rotated the gain control up and down on both channels. Test was done with gains all the way up.
Compare the signal level on both channels at each following point:
RCA input where it's soldered to the board
Back of gain pot
Each leg of the cap near the gain pot
Pins 3 and 5 of the op-amp closest to the RCA jacks.
You don't need to post the voltage for each, just compare and post where the signal varies significantly.
RCA input where it's soldered to the board
Back of gain pot
Each leg of the cap near the gain pot
Pins 3 and 5 of the op-amp closest to the RCA jacks.
You don't need to post the voltage for each, just compare and post where the signal varies significantly.
Tested everything and RCA's, Caps, Gain pot, and pins 3&5(op-amp closest to RCA's) are all testing good on both channels. I did check the op-amp closest to the main board and got zero on pins 3&5 if that helps.
Confirm that you get 1v on pin 5 and 0.3 on pin 7 of the op-amp closest to the RCAs.
It's normal to have 0v AC on pins 2, 3, 5 and 6 of the second op-amp.
It's normal to have 0v AC on pins 2, 3, 5 and 6 of the second op-amp.
Ok, This time I used a Fluke multimeter. With the left RCA supplied with 1v I measure 1v on pins 5&7. With the right RCA supplied with 1v, I get zero on 5&7 of the op-amp closest to the RCA's. Sorry, earlier test had both rca's connected at once, this time I did it one at a time. How is it that I get zero but still have some sound?
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