Author Topic: HP 54616B Schematics?  (Read 1872 times)

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Online EEVblog

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HP 54616B Schematics?
« on: March 18, 2017, 12:58:00 am »
Does anyone know of any schematics for the HP54616B?
There is a CLIP (Component level info package) for the 54000A series, but it's not the same.
Having keyboard & rotary encoder issues.
Front panel matrix diodes all look good, so I suspect the 74AC11244 drivers.
 

Online amspire

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Re: HP 54616B Schematics?
« Reply #1 on: March 18, 2017, 03:20:18 am »
Looks like the service manual has no schematics. I assume you have the service manual?
 

Online EEVblog

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Re: HP 54616B Schematics?
« Reply #2 on: March 18, 2017, 03:21:36 am »
Yes, the service manual is useless.
 

Online amspire

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Re: HP 54616B Schematics?
« Reply #3 on: March 18, 2017, 03:50:36 am »
Only thing I can suggest that may give some clues is the HP Journal (April '97) that discusses the design of this scope family. Talks a little about the architecture. Still no schematics unfortunately.

https://ia600409.us.archive.org/33/items/Hewlett-Packard_Journal_Vol._48_No._2_1997-04_Hewlett-Packard/Hewlett-Packard_Journal_Vol._48_No._2_1997-04_Hewlett-Packard.pdf
 

Online amspire

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Re: HP 54616B Schematics?
« Reply #4 on: March 18, 2017, 04:31:25 am »
Just one more thought, if the keyboard and rotary controller are slow to respond, check the 68000 processor is not getting spurious interrupts from somewhere. I have a different 68000-based instrument which is fully working, but has a very slow keyboard and this was on my todo list to check. I think there are 3 interrupt pins.
 

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Re: HP 54616B Schematics?
« Reply #5 on: March 18, 2017, 05:18:05 am »
Just one more thought, if the keyboard and rotary controller are slow to respond, check the 68000 processor is not getting spurious interrupts from somewhere. I have a different 68000-based instrument which is fully working, but has a very slow keyboard and this was on my todo list to check. I think there are 3 interrupt pins.

It's only a part of the front panel that doesn't respond or responds weirdly. Some buttons + some encoders in a group. The other controls work 100%.
Suspect a matrix line issue of some sort but I can't find it yet.
« Last Edit: March 18, 2017, 05:35:56 am by EEVblog »
 

Offline tautech

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Re: HP 54616B Schematics?
« Reply #6 on: March 18, 2017, 07:21:44 am »
Just one more thought, if the keyboard and rotary controller are slow to respond, check the 68000 processor is not getting spurious interrupts from somewhere. I have a different 68000-based instrument which is fully working, but has a very slow keyboard and this was on my todo list to check. I think there are 3 interrupt pins.

It's only a part of the front panel that doesn't respond or responds weirdly. Some buttons + some encoders in a group. The other controls work 100%.
Suspect a matrix line issue of some sort but I can't find it yet.
Interesting. I've been corresponding with a local guy with a DS1052E with very similar symptoms, quite a switched on cookie and when desoldering the nonresponsive encoder the thing came to life.  :-//
Sort of makes sense that one of the components on the front panel that could be subjected to physical stress might have had a cracked solder joint.
Sometimes it's something unbelievably simple.  ;D
Avid Rabid Hobbyist
 

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Re: HP 54616B Schematics?
« Reply #7 on: March 18, 2017, 08:48:20 am »
Turns out the CLIP schematics for the 54000A series are pretty much identical for the keyboard buffer section on the 54616B. Designators are wrong, but otherwise seems correct.
 

Online amspire

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Re: HP 54616B Schematics?
« Reply #8 on: March 18, 2017, 08:52:47 am »
Hope there is a video or two on this scope. Love seeing how HP did their magic particularly in the older designs.
 

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Re: HP 54616B Schematics?
« Reply #9 on: March 18, 2017, 10:21:40 pm »
Hope there is a video or two on this scope. Love seeing how HP did their magic particularly in the older designs.

Well I have shot 40min worth of repair footage. Whether or not I release that depends on whether I get ti fixed or not :->
Already fixed an ADC channel fault on it, but the keyboard one remains. Needs a bit more effort.
Resoldering the encoders and connectors didn't help, but I didn't expect them too, as an open or shorted encoder should just affect that one encoder, not others, they are only soldered on a single side of the board, not being used as vias even.
In any case I've measured the encoder contacts and they all seem to be doing their business.
« Last Edit: March 18, 2017, 11:03:06 pm by EEVblog »
 


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