2325 amp boards.. scratching my head.. please help

[xalara76]

Okay so I have a 2325 that had some issues when I got it. Relay would click on and off randomly amp boards offset would be around 53v and couldnt adjust to 0. Recapped amp boards, new heat sink transistors, resistors and output transistors etc. looks pretty damn good for my first time doing it. Checked over my work and instructions atleast 5x before installing. Relay will not engage at all now. Two spots on the amp boards are getting warm. ( see pics ) H715 as well as H706 & H707. The recap kit I bought came with ECB transistors for H707 and H706 so I bent the legs as instructed and installed.. H715 is ECB from the board diagram. Do I have H715 installed backwards ? See pic. Is H715 supposed to have the metal side towards the metal joint that screws into the heat sink ? I swapped in amp boards from another 2325 I have and the unit works perfectly. Btw, so its something on these pesky boards I re did

 

[sanjib]

For H706, is the letters on the transistors at the top and at the bottom as it is installed now?

 

[xalara76]

For H706, is the letters on the transistors at the top and at the bottom as it is installed now?

Not sure what you mean ? Perhaps these pics will help. I can read A1381 For H706 (new transistor I installed). Attached a close up of H707 as well.

 

[catrafter]

My two cents:
H706 and H707 are originally TO-202 devices, 2SA818 an 2SC1628 in every 2325 I have seen, I don't know if your parts are correct substitutes.
I have found it prudent to find and repair every problem before just swapping in new parts.
I never had much luck troubleshooting power amps with lots of negative feed back without an I/V tester.

Tom

 

[xalara76]

My two cents:
H706 and H707 are originally TO-202 devices, 2SA818 an 2SC1628 in every 2325 I have seen, I don't know if your parts are correct substitutes.
I have found it prudent to find and repair every problem before just swapping in new parts.
I never had much luck troubleshooting power amps with lots of negative feed back without an I/V tester.

Tom

Bought this kit off eBay from peace.love.music. Ben, a great guy with great reviews. Never had an issue with his stuff so I went ahead and bought the kit. It was annoying having to cross the legs for sure but I did it according to instructions. Pretty pissed cause everything looks like its in the right place and installed properly.

 

[xalara76]

My two cents:
H706 and H707 are originally TO-202 devices, 2SA818 an 2SC1628 in every 2325 I have seen, I don't know if your parts are correct substitutes.
I have found it prudent to find and repair every problem before just swapping in new parts.
I never had much luck troubleshooting power amps with lots of negative feed back without an I/V tester.

Tom

Do you think I should solder in the old transistors for H706 and H707 and see what happens ?

 

[xalara76]

Swap

My two cents:
H706 and H707 are originally TO-202 devices, 2SA818 an 2SC1628 in every 2325 I have seen, I don't know if your parts are correct substitutes.
I have found it prudent to find and repair every problem before just swapping in new parts.
I never had much luck troubleshooting power amps with lots of negative feed back without an I/V tester.

Tom

Swapped back H706 and H707 still no relay engagement. Are my power output transistors installed correctly?

 

[MBuras]

H715 should definitely not have the metal back touching any other metal. That’s why it’s mounted flat to the non-conductive board.

Make sure you didn’t use conductive thermal grease meant for computers. That would definitely be bad.

Also with the 2325 you can leave one or both amp boards unplugged to make sure the relay is engaging, then plug in one at a time to see which is causing problems.

Everything looks decent from the pics but we don’t know about any solder bridges, pieces shorted that shouldn’t be, what your actual silicon subs were vs. the originals to verify pinout, etc. Sure hope you can get it straightened out. The 2325 is amazing when restored. Just ask the guy who bought mine!

 

[xalara76]

H715 should definitely not have the metal back touching any other metal. That’s why it’s mounted flat to the non-conductive board.

Make sure you didn’t use conductive thermal grease meant for computers. That would definitely be bad.

Also with the 2325 you can leave one or both amp boards unplugged to make sure the relay is engaging, then plug in one at a time to see which is causing problems.

Everything looks decent from the pics but we don’t know about any solder bridges, pieces shorted that shouldn’t be, what your actual silicon subs were vs. the originals to verify pinout, etc. Sure hope you can get it straightened out. The 2325 is amazing when restored. Just ask the guy who bought mine!

Okay mine started to play ball randomly ! Relay engages after 5 seconds and is at 35V (perfect ! ) right amp board is at 61.1 and left amp board is displaying -58.9. Went to adjust R713 and it does absolutely nothing. Any idea ? Boards left board is now running warm around H706 / H707 (new transistors in kit) while right side I reinstalled the originals.. this is WEIRD LOL. Should I take out the left H706 / H707 and replace with originals as well ?

 

[sanjib]

I would suggest putting back all old transistors (if they were not tested bad) except small signals ones. Do you have a DBT?

 

[xalara76]

I would suggest putting back all old transistors (if they were not tested bad) except small signals ones. Do you have a DBT?

Well the power output transistors can stay atleast. Do you mean the on board heat sink transistors ?

 

[sanjib]

You can keep OT. But if you don't have DBT, you are risking damaging other components each time you power on.

 

[xalara76]

You can keep OT. But if you don't have DBT, you are risking damaging other components each time you power on.

Im okay with that. I can always bring it to an actual tech to have him look at it im just curious why I cant get the bias adjusted for the channel.