PK-232 mods op amps

PK232 mods  for op amps  10-03-89
There is a lot of rubbish between the pins 4 and 11 of u23, 26, 28,30, 32 and 34. so I placed some 1uf caps across them and my receive noise (measured on a mark-space scope cross-display) is much much less. In fact, I can now even copy some steady signals that dont even raise the s-meter needle. Consequently I bought from radio shack 6- 1uf tantalum capacitors and mounted them on the bottom of the board, with the shortest possible leads in the positions described above. The results are outstanding. Rtty signals I could not copy before ,now copy perfectly, even when
you can barely see the traces on the scope. Arq links which could not be made before ,now flow smooth.
The only thing I dont know is if the mod will work if the latest version of the pk232 firmware upgrade is not installed, but I would think that it will.

P.S. the part number for the referenced capacitors:
   radio shack part no 272-1434
   1uf 35 volts (tantalum)
   cost .59 cents each

The most difficult part is identifying the op-amps and the pins but here is a hint… the pins 4 and 11 are the middlemost pins on both the top and bottom rows of the chip, so its really hard to make a mistake.
GW1NGL NA7KR Kevin Roberts Ham Radio

Page last updated on 09/10/2012 by Kevin Roberts NA7KR a colection of Ham Radio and Electronic Information