开云体育

Does anyone know which of the ribbon connectors on the 7104 power supply that can be safely detached to determine which is causing excessive loading? Also, which of the 7000 Series oscilloscopes use the same power supply as the 7104?

It may be worth looking at the output of the opamps in the PSU current sense sections of the circuit.

In mine the 5V lighting circuit was shorting inside the PSU and that was the only way I found the problem.

Dave

Off the top of my head I don't recall, but there is a great cross reference (should be in the files section) of scope models vs PCBs types/numbers.
-Dave?

------------?Also, which of the 7000 Series oscilloscopes use the same power supply as the 7104?

Also, which of the 7000 Series oscilloscopes use the same power supply as

the 7104?
I think the 7854 uses the same PSU.

PS: I noticed on my 7854 that PSU tends to switch to overload mode if
filtering capacitors are worn out. I recapped mine and since then it has
been working without a glitch.

Best Regards,
Nenad F.

Hi Nenad,
Were you able to find exact replacements, including same form factor, for the filter caps in your 7854?
If so do you recall where you bought them?
That would save some of us with 7854s that will need to freshen up our power supplies the time consuming task of locating exact replacement power supply caps.
Thanks,
Dennis Tillman W7PF

On Thu, Oct 4, 2018 at 07:02 PM, Gary Robert Bosworth wrote:

Also, which of the 7000 Series oscilloscopes use the same power supply as the
7104?

The P/N of the complete P/S is 620-0283-01 or -02. -01 was also used in R7103, 7854 and 7904A.
It was replaced by the -02 which was used in the above plus 7704A B231888 - up and 7934.

/H?kan

Are the 620's all power supply assemblies a listed category in the RPR or does RPR only group individual items or parts?? I know it is a column in the list but are all the 620's on one or several microfiche slides.

If so, maybe that series would be a good one to ask Dave Brown to scan from microfiche.? But,? I think I used up my request quota on the 151 series.? Although PS's shouldn't be 762 pages.

The advantage of OCR'ing would be you could search the file by model, part number, assembly number.

Bob.

On Fri, Oct 5, 2018 at 08:03 PM, bobh@... wrote:

Are the 620's all power supply assemblies a listed category in the RPR or does
RPR only group individual items or parts?? I know it is a column in the list
but are all the 620's on one or several microfiche slides.

The RPR isn't grouped it just lists all P/N's in sequence from 000-xxxx-xx thru 950-xxxx-xx.
In my set, from 1997, 620-xxxx-xx are on pages 28385 thru 28420 = 36 pages.

/H?kan

Ok, thanks - appreciate the knowledge you bring to the group H?kan.

Bob.

Hi Denis,

Unfortunately no, but the trouble is limited only to those axial types.
When it comes to low ESR 105*°*C I usually stick with
Nippon/Rubycon/Nichicon, and these (modern) are all radial (I get mine from
China via eBay, local dealers in my country have a really poor selection in
this category).
Other caps in this PSU are easy to match in size, e.g. Nippon has a decent
selection of 100V parts, and since you don't really need the highest spec
parts here you can easily find replacements. IIRC the 12.5mm can diameter
is OK for the +54V and -54V rails, and most of these are short in height.
And I readily use larger values when recapping PSUs, sometimes up to twice
the original value.
Anyway, I kept the old caps for sentimental reasons, maybe someday somebody
decides to make an exact restoration...

Best Regards,
Nenad Filipovic

On Fri, Oct 5, 2018 at 5:56 PM Dennis Tillman W7PF <dennis@...>
wrote:

Hi Nenad,
Were you able to find exact replacements, including same form factor, for
the filter caps in your 7854?
If so do you recall where you bought them?
That would save some of us with 7854s that will need to freshen up our
power supplies the time consuming task of locating exact replacement power
supply caps.
Thanks,
Dennis Tillman W7PF

While I consider Rubycon to be a first tier mfr, I once had an issue with their bleeding edge flash caps.? Nichicon and Rubycon offered caps with identical specs on paper, but either the Nichicons had a little wiggle room and were under spec'd or the Rubycons were of lessor quality. The design was running right at the edge of the envelope and the Rubycons were literally blowing up. Never had any issues with the equivalent Nichicons.??
-Dave?

From: Nenad Filipovic <ilmuerte@...>
To: [email protected]
Sent: Saturday, October 6, 2018 12:56 AM
Subject: Re: [TekScopes] Loading of 7104 power supply

Hi Denis,

Unfortunately no, but the trouble is limited only to those axial types.
When it comes to low ESR 105*°*C I usually stick with
Nippon/Rubycon/Nichicon, and these (modern) are all radial (I get mine from
China via eBay, local dealers in my country have a really poor selection in
this category).
Other caps in this PSU are easy to match in size, e.g. Nippon has a decent
selection of 100V parts, and since you don't really need the highest spec
parts here you can easily find replacements. IIRC the 12.5mm can diameter
is OK for the +54V and -54V rails, and most of these are short in height.
And I readily use larger values when recapping PSUs, sometimes up to twice
the original value.
Anyway, I kept the old caps for sentimental reasons, maybe someday somebody
decides to make an exact restoration...

Best Regards,
Nenad Filipovic

On Fri, Oct 5, 2018 at 5:56 PM Dennis Tillman W7PF <dennis@...>
wrote:

Hi Nenad,
Were you able to find exact replacements, including same form factor, for
the filter caps in your 7854?
If so do you recall where you bought them?
That would save some of us with 7854s that will need to freshen up our
power supplies the time consuming task of locating exact replacement power
supply caps.
Thanks,
Dennis Tillman W7PF