H Len,
I don't think the 100V is bad the ripple was only 60mV and it always looks stable. But I would look the fool if it turns out to be the problem....! Yes, 60 mV in 100 V seems small but it would be good to eliminate it.
I will replace it when I get the chance.
It was late when I was looking at the ICs so I did not think too hard about speed and voltage. The 74hc4538 is pin compatable, I will have to check the other specs. If I need to I can fashion up an adapter for whatever chip works.
Are you familiar with Tek manuals? No. I see a timing problem..maybe...I am not sure. The manual shows 15 waveforms on one page the first is the input 1-KHz signal. Then the others are for various signals such as; HOLDOFF GATE, SWEEP, END OF SWEEP etc. The thing is that if these waveforms are relative to each other then all the signals are about twice as fast as they should be relative to the 1-KHz input. I am not sure if the input is related to the others however it does seem that all the other signals are relative in time to each other. I would need to see the circuit and the waveforms to be able to offer an opinion.
I am using a PC scope program to look at signals...it is ok but no DC of course. That is why I am looking at sweep and holdoff generation as these signals look bad compared to the manual. This is a LOOP......it is hard to know where the problem starts. That is why the 96ls02 is a possible, I check the caps around it..ok..but the waveform is not as it should be...but it does get triggered by a filp flop which also has bad waveform....which is driven by the 96ls02....as I said...a loop.
The PC scope would be very limited in bandwidth, ie. the sample rate may be too slow.
I need to think about this more....or maybe less..!
Thanks.....Ray