Fender Champion 30 No Output

[Delta362]

I'm working on a Fender Champion 30 that the owner said powers up, but has no output. The power supply voltages all look good. I traced the input signal all the way thru to pin 1 of the output amplifier chip, but have no voltage on the output pin. The amplifier is the TDA1514A, which I realize is long discontinued. I have 0V for all pins except:
Pin 4 has -26.9 VDC (good)
Pin 6 and Pin 7 both have +26.9VDC (good).

Pulling the board, it shows signs that this amp had previously had all opamps replaced or resoldered, and the pot housings and jacks resoldered, and the output amp resoldered. It didn't look to be replaced, but can't guarantee that.

What additional checks can I do to verify if the output amplifier is or isn't working properly?

If this amplifier chip is bad, got a suggestion on a substitute that I could mount and wire in if the pinout is different? This amp has sentimental value to the owner, so he's wanting to get it fixed, if it can be made functional without being too costly. Thanks!

[The Dude]

Normal failure mode of those IC's is a short causing the mains fuse to open. Sure it's entirely possible that the IC failed in some other way. Did you check the output right at the IC, or the jacks? The external speaker jack is a switching jack that disconnects the main speaker when an external speaker is used. It's possible you have a bad switching jack. Plug a speaker into the external speaker jack. Does it work? If so, clean or replace the switching jack. Is the IC muted? Check the voltage from pin 3 to pin 4. Below is a link to the IC datasheet.

http://pdf.datasheetcatalog.com/data...ps/TDA1514.pdf

[The Dude]

If you do need the output IC, I couldn't find an OEM/NOS version from a reliable source. I did find the NTE equivalent here, although quite expensive. They have 82 in stock:

https://www.ntepartsdirect.com/ENG/P...SABEgIA0vD_BwE

[g1]

I couldn't find an OEM/NOS version from a reliable source.

Dalbani have some pulls on their ebay store, around $30 shipped.

[Delta362]

Output was checked right at the amplifier output (TP17). I even inserted a speaker cable (with speaker) to the external jack and tested TP17 with no change.

Pin 3 remains at 0V. If I read the datasheet correctly, this would be a few volts positive if it's in mute condition.

I checked the resistors and caps around the circuit and they measure per print (one leg lifted if needed to isolate the component. No broken solder joints or bad traces found. Continuity existed between the components as designed. That's leaving me to think it's the output amplifier, though I would have expected it to hit a rail on the output instead of no output signal or voltage.

I looked at the Dalbani Global on eBay. Is this the correct store? I'm seeing the TDA1514 and TDA1514AQ, both around the $11-13 mark with free shipping (much less than $30). Are these the correct ones?

What's the difference between those two (TDA1514 vs TDA1514AQ) as they look about the same and I didn't find an AQ datasheet?

[Delta362]

Just measured 3 relative to 4. It's 27VDC. The datasheet max says 7.5VDC. Seems the chip is bad. Agree?

[g1]

I looked at the Dalbani Global on eBay. Is this the correct store? I'm seeing the TDA1514 and TDA1514AQ, both around the $11-13 mark with free shipping (much less than $30). Are these the correct ones?

What's the difference between those two (TDA1514 vs TDA1514AQ) as they look about the same and I didn't find an AQ datasheet?

I think it was detecting that I am in Canada, so it did not offer me free shipping. Yes, those are the correct ones.
Not sure about the Q suffix, I thought it may have to do with the bend of the leads. The picture looks like they are straight though.

[Delta362]

Thanks! I'll order the non AQ version and see how it does.

[Delta362]

Got the TDA1514 in from Dalbani from eBay today. Thanks for that lead! I typically don't buy electronics from eBay, but you put my mind at ease.

It was easy to remove the old one and install the new one. Amp is back to working properly. Thank you!