PL Model 700 Series II with LEDs that just won't work!

Well that is a relief

while in Mexicon I came across the first schematic of a op-amp
check it out
 

Attachments

  • image.jpg
    image.jpg
    76.7 KB · Views: 24
  • image.jpg
    image.jpg
    98.9 KB · Views: 21
If anyone is going for the blue LED conversion, I'd be interested in a single stock red one. I have one with a dead pip in it that I've not gotten around to shuffling down to the overload indicator spot. Its bad right about the 3 watt level, which is about as loud as it gets for me.
 
laatsch55 said:
For what it's worth, the only 1237 IC's that are available for Don's DC protect 400 boards are chinese knockoffs of NEC's........they have worked in everyone I've done so far, that's about 15 in number. I can't say that would happen in your case, BUT, a guys not out much bread by trying. I think they were 1.15 each. Whether or not they will stand the test of time remains to be seen...
Click to expand...

I Have a colleague who lives in Beijing. On his recent trip I had him pick up a hundred for me. Havent tried yet but would assume they're OK. On the LEDs, a customer found replacements on digikey last year He gave me his old ones.

I'm not sure the LM39xx chip is a good alternative. The PL circuit uses a compressor to squeeze 45db down to 20db and has a fast attack slow decay circuit for the peak detect. I don't think these other chips do this.
 
Last edited:
Update on this...I replaced both ICs and the Opamp on both boards and we are back in business on both LED boards...all caps and diodes were replaced previously as well.

Also, I bought a stash of both the blue and red 10-segment new style LED bars and Dremel cut down one of the 10 segment red and blue to 6 segments so everything fits nice. The blue is very cool, but to avoid looking orange, the red filter would need to be changed to blue. The new red LED bars are a huge improvement over the original and I may just leave it red. I'll post pictures of the blue on the board and the red from behind the filter to give you the idea of the brightness.

thanks for all the help guys!
 
bhuskins said:
Update on this...I replaced both ICs and the Opamp on both boards and we are back in business on both LED boards...all caps and diodes were replaced previously as well.

Also, I bought a stash of both the blue and red 10-segment new style LED bars and Dremel cut down one of the 10 segment red and blue to 6 segments so everything fits nice. The blue is very cool, but to avoid looking orange, the red filter would need to be changed to blue. The new red LED bars are a huge improvement over the original and I may just leave it red. I'll post pictures of the blue on the board and the red from behind the filter to give you the idea of the brightness.

thanks for all the help guys!
Click to expand...

Glad you are back in business. Prior lightning strike or someone had it wired for 120 and plugged it into 240. For both boards to be bad in that manner, it is one or another.
 
Lightning strike ruin a piece of Audio equipment????? Like that ever happens.....;-)
 
Na, we just roast 15,000.00 VFD's, and 5,000.00 motors....
 
You must log in or register to reply here.
Back
Top