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David- I have one off a 221, PM with your mail address. mike

Ok, next try unplugging the readout board power connector. P-2171 is the power. If that doesn't help, then try the output board power connector.P-1066. You might also plug in a good pair of modules

Hi Tom- Thanks for the suggestion. I did as you suggested and lifted one side of R1603 (it's 2.2K), but with the same result. Of course the neon bulbs don't light since they are on the HV circuits,

Hi, The black plastic feet on tm500 power supplies work well on 465s Jerry Massengale

Having been through the 4xx crumbling rear foot problem several times, I made up some replacement feet out of plastic bar stock. Attached are some pictures of these new feet. The power cord wraps

Hi David, Thanks for that info. That explains why Bob Parker's name comes up so often in this context along with Dick Smith's name. Bob's design is wonderful and his user interface is truly brilliant.

Hi Raymond, When I bought my 465 it also had the disintegrating rubber feet. Since they are also used as cable wrap I wanted to replace them and found a set NOS from a reputable seller. I bought them

Hi Tom, Our messages crossed, will go shopping!

Tom, It turns out that the original diode is a 20V 5A Schottky, 1N5823... Do you think 50KHz is too high for the 1N5406, taking the noncritical place into consideration?

Hi Raymond, Today I found a 7704A service manual, and it says that CR3182 is a 1N5823 which is a 5 amp Schottky diode. You might want to do some diode shopping soon. tom jobe...

Hi Tom, Thanks for thinking for me! I hadn't given this even a moment's thought! Obviously, my electronic alertness is a bit off after having been out of it for around 20 years... You're right about

Hi Keith, You might try lifting one end of R-1603 on the high voltage board A-18 and seeing if the power supply will come up. Note the value of the resistor as it is a selected part. This would

Fabio, If you have a 7103, a 7A29 vertical plugin and a 7B10 or 7B15 Timebase will get you 1 GHz bandwidth. For larger bandwidth you have to use sampling plugins. John VE3XRY

Hello all, I'm working on a little Tek 211 and one of the position knobs fell apart while I was disassembling the A1 input circuit board to go through the adjustments. Part # is 366-1322-01. I think

I have been reading the thread about Raymond's 7740A with interest, as my problem seems similar. I have a R7903 which is in some kind of protection mode. I can watch the power, indicated by the two

The time constant is likely to be less than an hour in either case, probably much less if the case is vented, so it will only make a difference against temperature changes that are faster than that.

Hi Raymond, A question about your diode substitution. What frequency does that diode run at in the 7704A? And is the 1N5406 suitable for that frequency? The data sheet for 1N5406 makes me think it is

Hi Raymond, You will soon need a larger shack if you continue collecting that fast :=). Congratulations that you found the fault so quickly! It's a calibration requirement that will guarantee that

Hello guys, I have been able to repair my 7704A! It turned out that one bridge rectifier diode (CR3182) on the inverter/rectifier board was shorted, causing a periodic short-circuit in transformer