Re: 7603 Strange HV Need Help

Marian B

On 20.01.2016 02:03, go_boating_fast@... [TekScopes] wrote:

Readout Board definitely bad. Two ICs are so corroded the pins no longer
connect and some IC pins fell off when I attempted to remove them using
an IC puller tool. The IC pins are not gold plated like the rest of the
ICs, so they may have been replacements. I will likely need to replace
the sockets due to the corrosion.

U2155 156-0043-00 Quad 2 input pos nor gate
That's a relabeled 7402 ; in later units they are not re-labelled anymore.

Generally speaking it seems to me that real Tek ASICs were mostly or
exclusively gold plated DIPs (- no problems with the dreaded TI
sockets), while ordinary ICs, be it under their actual name or
relabelled, usually have tinned pins prone to these issues, especially
in the TI sockets.

Cheers, Marian
U2250 156-0032-00 4 bit binary counter sn7493an

U2120 (same part as U2155) is also not gold plated although not badly
corroded,yet. I will replace that also.


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