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Re: Checking HP 8672A output level: are these drops normal?
50 years a microwave engineer But poor reading skills OP defined the problem as only measuring the amplifier. How is it such experience cannot read and stay in context with OPs question? If you are so
By Dave Me <scope.project@...> · #145434 ·
Re: Checking HP 8672A output level: are these drops normal?
This is not good advice. The amplifier, to a first degree,CAN be tested with the isolators intact. This is the standeard working environment and the isolator protect the amp in-situ, thats why tey are
By Jeff Kruth · #145433 ·
Re: Checking HP 8672A output level: are these drops normal?
"Will you destroy the amplifier if the output is not loaded with 50 ohm?" This is microwave-energy. (6 GHz?) It is critical to have the exact characteristic else energy is reflected, not included in
By Dave Me <scope.project@...> · #145432 ·
Re: HP 8566B - Can my high voltage transformer be faulty?
BTW, I removed and still have the HV section from an 85662A when I upgraded to an LCD. If you need parts... J.Kruth
By Jeff Kruth · #145431 ·
Re: Checking HP 8672A output level: are these drops normal?
I do have a HP437B with a 18 GHz power sensor so measuring the power is not a problem. The issue is that it is not easy to disconnect the SMA connectors between the amplifier, isolator, high pass
By Erik Kaashoek · #145430 ·
Re: HP 8566B - Can my high voltage transformer be faulty?
The PDA supply MUST be stable and regulated or the size of the CRT image will keep changing, Also not a good idea to operate long term without load on high voltage winding of the HV transformer. If it
By george edmonds · #145429 ·
Re: HP 8566B - Can my high voltage transformer be faulty?
Idea. The flyback and HVM simply make a high DC voltage and low current (milli-ampere"?) Maybe this to replace a difficult to find HVM? Adjustable HV-DC output: amazon DOT
By Dave Me <scope.project@...> · #145428 ·
Re: Checking HP 8672A output level: are these drops normal?
I do not know this instrument. I assume the path of amplifier is 50 ohms? A suggestion on "checking power level" is to use a microwave detector diode (of the type like BAT1504) and a short coaxial RG
By Dave Me <scope.project@...> · #145427 ·
Re: HP 8341B Firmware Questions
For the records: I have an HP8340A with firmware rev. 23 of May 1985, serial prefix 2602A, which works flawlessly with my HP8510C firmware 7.14 of August 1998. Tom
By tom_iphi · #145426 ·
Re: HP 8341B Firmware Questions
Hi, My prefix is 2928A so later than that. It mentions a "minimum of bugs" so I'm not sure which bugs the May 88 firmware might lead to, but I have not noticed any problems. Best regards, Job
By Job PH4AS · #145425 ·
Re: Checking HP 8672A output level: are these drops normal?
Back to repairing the 8672A The indicator lights are now all repaired but the low output level problem is still there. It would be nice to be able to check the output level of the power amplifier as I
By Erik Kaashoek · #145424 ·
Re: HP 8341B Firmware Questions
Hi Job, Thanks for the reply. That's great to hear, I was a bit worried since I only have the May88 version as well. FYI, I got this is info from the 8510C Service quick reference guide (see the last
By saevar · #145423 ·
Re: HP 8566B - Can my high voltage transformer be faulty?
Hi George, I couldn't wait so I tested the method you suggested immediately and you were absolutely right. There appears a small green "window" visible (like a miniature image) on the CRT in the
By saevar · #145422 ·
Re: HP 8566B - Can my high voltage transformer be faulty?
FWIW, I had a very similar problem with my 3585B spectrum analyzer. I¡¯m my case the flyback had shorts. The circuits are very similar and the supply fuse (18V) would blow on power up. ?You can do a
By Jeremy B · #145421 ·
Re: HP 8566B - Can my high voltage transformer be faulty?
Hi again Saevar I should add that if the HV multiplier has failed the oscillator will not be able to start and will draw a high current due to the load on it, it will then blow the safety fuse, just
By george edmonds · #145420 ·
Re: HP 8566B - Can my high voltage transformer be faulty?
Hi Saevar Experience, experience and experience. I have been repairing oscilloscopes now for almost 65 years. Rule one, the higher the operating voltage the more likely to fail also frequently the
By george edmonds · #145419 ·
Bubble Memory Reseed
Hi All, To reseed the bubble memory on the HP3561A DSA, a special 'reseed module' is required. It was probably made by Intel. Has anyone done this successfully and know where the reseed module can be
By John Buie · #145418 ·
Re: HP 8566B - Can my high voltage transformer be faulty?
Hi all, Thanks for your valuable advice. George, what makes you conclude that the A1A11 is faulty? I am not that familiar with CRT circuitry and am therefore a bit lost as to how to test these various
By saevar · #145417 ·
Re: HP 8566B - Can my high voltage transformer be faulty?
And 15,734 Hz in the US (NTSC). -- Prof. Thomas H. Lee Allen Ctr., Rm. 205 420 Via Palou Mall Stanford University Stanford, CA 94305-4070 http://www-smirc.stanford.edu
By Tom Lee · #145416 ·
Re: For HP 8660 Power Supply Load Question please?
Thanks! very good. The ~ 17 ohms is the lamp and dropping resistor inside the manual fine tune encoder. Im seeing another 10 ohms cold load thru the Gpio boards apparently to or from the Xtal Oven
By Dave Me <scope.project@...> · #145415 ·