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Mark

Thanks for the reply

The one I have is serial #B141271 It’s the R7844 I have another 7844 serial B142533 with exactly the same problem but on both beams, The one with out this problem is B121284.

If I could trouble you Page 3? The rest of these references on what board?

Thanks again

Mark

I don't recall who owns the domain and maintains the storage etc... To look
a bit closer into it. Can anyone please remind me?
I see a "Proxy Protection LLC" on whois, but that doesn't tell me anything.
I see it still down.
Radu.

On Wed, Apr 23, 2025 at 6:26?PM Jim Ford via groups.io <james.ford=
[email protected]> wrote:

Back to the Log In Required mode, evidently.

Jim Ford
Laguna Hills, California, USA

On Apr 23, 2025, at 2:27?PM, jeff_a_bowman@... via groups.io

<jeff_a_bowman@...> wrote:

?I have had a few minor problems lately, but it is usually back working

in a few minutes or hours.

Jeff

--
Jeffeelcr

hey folks I plan to open up my Tek T922 scope in the next couple days to hit all the contacts with contact cleaner & reseat the boards & connectors . It looks like 3 screws on top spine & another 3 screws lower spine . Is there any other fiddleing I need to worry about with the front or rear cover ?

thanks

animal

It looks like there isn't a page for the 1424 at TekWiki. Are you up for creating one?

There are paper manuals on eBay.

-Thomas

Back to the Log In Required mode, evidently.

Jim Ford
Laguna Hills, California, USA

Hi Morris:
Thank you for the tips. Finally got my hands on a VTVM, but alas, the highest range is only 1500V.

Checked some voltages and they're definitely wonky. Going to re-cap as much as I can to see if there's an improvement and will report back.

Gordon

Mark,

The s/n of the piece will make a difference. If below 60000, it is likely the tunnel diodes on page <3> are bad. I have had this problem before. These going bad will cause your problem from what I saw. I did replace the leaky 0367 transistors in the ones I have that tested leaky, diode, from C to E with KSP10BU. The leakage did cause triggering and other problems in mine. Resistors R479 and R939 should be 1W. I have found a transistor open that is on the lower left of a page which I do not remember that is run almost at its voltage rating. I did use the above number as a replacement. This transistor is part of a board schematic.

Mark

I have had a few minor problems lately, but it is usually back working in a few minutes or hours.
Jeff

--
Jeffeelcr

It was down with 503 errors

Has been back since around 7 pm BST (GMT+1)

Is anyone else having issues with TekWiki today? I attempted to look up an instrument, but received a message stating that a login is required. I don’t have an account, so I can’t access anything past that.

Team,

I have over the past few months acquired 5 7844 scopes, none of which worked. Good thing it was just the cost of picking them up. I have repaired 3 of them so far, one of them still has the power supply on the bench, one was the parts source. On the latest project a R7844, after replacing caps in the power supply, replacing beam 1 vertical amp twice, original was very noisy, first replacement gain was very compressed on the positive side. Working very well now, calibration done. Discovered one last problem. Intensified sweep using a 7B92A. Beam 1 works perfectly, beam 2 the delayed intensified sweep is very dim . Intensity control does control it but at max you can just discern on the screen. Reducing the separation until it corresponds with the main trace it works perfectly.
Now for the weird part if I use the older 7B92, intensified Alt trace, it works perfectly

Thoughts?

Mark
W7HPW

Real Radios Glow in the Dark

Oops
7pm BST (GMT+1)

so shortly after your message appeared here, it was back up ok

Wiki was down
Back up by around 7pm...

It took me on a journey checking that the hosting wasn't being DOGEd.

?

Anyone have a manual for the 1424?
Wiki Down?

Sam

Hey Bobert(?),

I guess you have to go back to basics. Since the scope worked before you
touched the A5 board, most likely you broke something while you were in
there. It happens.
What's the story of this scope? Is it new to you?
What do you have in terms of other gear to diagnose things? A second scope
would be super helpful after a point.

If the FP lights are staying on, then I think the microprocessor (MPU) is
likely not doing its job.
If J503 on the A5 board is in the DIAG position, that would explain it
(unlikely, but I thought I'd mention for completeness).
After that I'd go look at the MPU. Does it get power? Is it stuck in reset?
Is the clock good?

Siggi

On Wed, Apr 23, 2025 at 6:12?AM Bobert29 via groups.io <jg1647=
[email protected]> wrote:

3 cables A5 to A1
2 cables A5 to FP
1 cable A5 to PSU
All connected

One quick bit: Don't use that 10meg resistor (or any other ordinary
resistor) again for HV measurement. A typical voltage rating for a
half-watt resistor is just a few hundred volts, above which HV will arc
through/around it, effectively shorting it out. If you don't want to
blow things up, you'll have to use a proper HV probe.

Appreciate concern - I am actually using a high-voltage resistor rated for 10KV, which I happened to have available. It's a few inches long to prevent arcing. But the load is too high to measure anything that can't source a milliamp.

You can use a ECG/NTE538

Thanks. These are relatively cheap and available. I see the original Tek part had a series resistor at the end, was that just for technician safety?

You can use a ECG/NTE538

/g/TekScopes/message/40834
/g/TekScopes/message/99186
/g/TekScopes/topic/7652826

/g/TekScopes/topic/7633997

/g/TekScopes/topic/475_dead_voltage_multiplier/7648063

3 cables A5 to A1
2 cables A5 to FP
1 cable A5 to PSU
All connected

I hate those when they are used as transistor sockets !
The lead dress is slightly different to that used in most transistor
testers, so when I pull a x'istor to test, I need to spread the leads a
little to get it back into its socket.
I am currently working on a 5L4N which is full of the things.
Tim P


On Wed, 23 Apr 2025 at 10:03, David C. Partridge via groups.io
<david.partridge@...> wrote:

<>



Cheers, David

<>



Cheers, David