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Re: 7B53A - "Hook" at trace start in Mixed Sweep mode

SCMenasian
 

It would be good to know whether the "hook" changes if you change the sweep speeds (both) and what the nature of the changes, if any , are.

Stephen Menasian


Re: 7B92 with no repeating sweep

Mark Vincent
 

Jeff,

Swapping boards is a good way to determine problems. Swapping ICs would be next to see if any are bad.

Removing the trigger light is easy. It snaps in. Pry the black cap of the back. You can ohm out the lamp to see if it is open before removing the cap. If the lamp is bad, it is a 683.

The knobs on the time base have a narrow range of position when put back on. If the large knob is put on too far back, it will do what you are seeing. There will be too little back movement. Move the knob out a bit to see if that helps. Cleaning the switches will help. You may have to remove the board to get access to the set screws on the part that moves the switches if moving the knob does not help. Make sure not to allow the cams to turn if you remove the board! Be sure not to loose the pin that pushes the nylon bobbin that actuates the microswitch lever. The clear part that shows the time/div. adjusts the amount of movement. That also has a narrow range it can be secured to open and close the switch.

The Var. control can come out by loosening the set screws on the collar that is connected to the black part to the control. You do not need to remove the readout board to do this step.

You may have to have both shafts out to get them straight.

Mark


Re: 7B92 with no repeating sweep

 

So I got a second 7B92, and this one mostly works (TIME/DIV shafts are bent, trigger lamp does not illuminate, something wrong with ALT horizontal mode when TIME/DIV knob is pushed in, and delayed sweep triggering is wonky), so I'm planning to swap boards between the two units to narrow down the location of the fault (or try to make one fully working unit, though I'd prefer to fix both).

My first questions is: is this a good plan, or am I likely to spread the failures around?

Second question is about the faults in the new unit:

1. The trigger indicator does not light. How difficult is it to replace that lamp? It doesn't look like I can remove the lamp from the back; do I need to pull the face plate (and all the knobs) off to replace the lamp, or am I missing something obvious?

2. The problem with ALT mode appears to be that the TIME/DIV knob does not return all the way when pushed in, and the slide switches behind the cam-switch housing are not closing in their back positions. Is there a way to adjust the position of the actuating flange on the outer shaft, or do I need to disassemble the knob and perform some kind of maintenance on that?

3. I have managed to straighten the TIME/DIV shaft by brute force, without removing the shaft from the unit, but it's still messed up. I had expected to be able to release the VAR/CAL shaft from behind the cam-switch housing just by loosening a set screw, but it turns out that, unlike the same shaft in the 7B53A, this one has a flange on the end that prevents it from being extracted through the outer shaft. Is there a way to remove the CAL/VAR shaft that doesn't involve complete disassembly of the cam-switch?

4. If worse comes to worse I suppose that I can swap the entire TIME/DIV cam-switch assembly between the two units. I know that I'm not supposed to remove the screws on the back of the cam-switch (the ones that also hold the readout board to the cam-switch body), but is it safe to remove the entire cam-switch body from the main interface board?

-- Jeff Dutky


Re: 7B53A - "Hook" at trace start in Mixed Sweep mode

n4buq
 

I added a photo here:

https://groups.io/g/TekScopes/photo/252850/3326143

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "n4buq" <n4buq@...>
To: "tekscopes" <TekScopes@groups.io>
Sent: Monday, October 25, 2021 10:37:13 AM
Subject: Re: [TekScopes] 7B53A - "Hook" at trace start in Mixed Sweep mode
That's correct. Only in mixed mode.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Jeff Dutky" <jeff.dutky@...>
To: "tekscopes" <TekScopes@groups.io>
Sent: Monday, October 25, 2021 10:25:29 AM
Subject: Re: [TekScopes] 7B53A - "Hook" at trace start in Mixed Sweep mode
It sounds to me like the beam is being "unblanked" a little early and you are
seeing part of the retrace.

Are you saying that you only see this in mixed mode? Not in regular sweep mode?

-- Jeff Dutky




Re: 7B53A - "Hook" at trace start in Mixed Sweep mode

n4buq
 

That's correct. Only in mixed mode.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Jeff Dutky" <jeff.dutky@...>
To: "tekscopes" <TekScopes@groups.io>
Sent: Monday, October 25, 2021 10:25:29 AM
Subject: Re: [TekScopes] 7B53A - "Hook" at trace start in Mixed Sweep mode
It sounds to me like the beam is being "unblanked" a little early and you are
seeing part of the retrace.

Are you saying that you only see this in mixed mode? Not in regular sweep mode?

-- Jeff Dutky



Re: 7B53A - "Hook" at trace start in Mixed Sweep mode

 

It sounds to me like the beam is being "unblanked" a little early and you are seeing part of the retrace.

Are you saying that you only see this in mixed mode? Not in regular sweep mode?

-- Jeff Dutky


Re: 7B53A - "Hook" at trace start in Mixed Sweep mode

n4buq
 

I should add that, other than changing the position of the "hook", changing the SLOPE and/or the LEVEL setting has no effect on this.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "n4buq" <n4buq@...>
To: "tekscopes" <tekscopes@groups.io>
Sent: Monday, October 25, 2021 8:45:47 AM
Subject: [TekScopes] 7B53A - "Hook" at trace start in Mixed Sweep mode
If I set one of my 7B53A plugins to mixed sweep mode, the very start of the
trace shows a slight hook-shape where the trace moves to the left before
starting a full waveform. The remaining waveform, including the faster sweep
part, is normal. My other working 7B53A does not show this.

I'm not sure, but I think I've seen a post regarding what I'm seeing in the past
few weeks and I think the suggestion was that this is due to some oscillation
and comments pointed to a particular part/section; however, I might have that
confused this with a website, etc., and not a post here.

Anyone familiar with this phenomenon and, even better, have a suggestion as to
where to look for the problem?

Thanks,
Barry - N4BUQ



Re: TDS3044B repair

 

On Mon, Oct 25, 2021 at 01:40 PM, Jay Walling wrote:


Not really feasible, the 2 channel variants are missing the A/D converters,
the attenuators, and all the passives around the attenuators.
Quite. Not speaking of the modifications of case and front plate. Repairing a 3014 using parts from a donor-3012 may be feasible but without documentation, which AFAIK is not available, that'll be quite a task as well in many cases.

Raymond


7B53A - "Hook" at trace start in Mixed Sweep mode

n4buq
 

If I set one of my 7B53A plugins to mixed sweep mode, the very start of the trace shows a slight hook-shape where the trace moves to the left before starting a full waveform. The remaining waveform, including the faster sweep part, is normal. My other working 7B53A does not show this.

I'm not sure, but I think I've seen a post regarding what I'm seeing in the past few weeks and I think the suggestion was that this is due to some oscillation and comments pointed to a particular part/section; however, I might have that confused this with a website, etc., and not a post here.

Anyone familiar with this phenomenon and, even better, have a suggestion as to where to look for the problem?

Thanks,
Barry - N4BUQ


Re: TDS3044B repair

 

Your question was about converting a two-channel TDS3012 to a 4-channel version (TDS3014). I can imagine >that not a lot of people would be able to answer such a question, knowing that precious little is known about these >'scopes technically, both hardware- and firmware-wise.
I can answer that, anyway. Not really feasible, the 2 channel variants are missing the A/D converters, the attenuators, and all the passives around the attenuators.


Re: TM500 tester switch - Attn. Jared Cabot.

Colin Herbert
 

Ah, But that order was from Mouser, not DigiKey like mine. My switch was just in a bubble-wrap bag in another plastic bag.
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Shaun M
Sent: 24 October 2021 19:37
To: TekScopes@groups.io
Subject: Re: [TekScopes] TM500 tester switch - Attn. Jared Cabot.

Colin,

I purchased the parts for this project from Mouser in January of this year. The Grayhill switch we are discussing arrived packed a plastic tube and included the pins, stickers and paper instructions for configuring it.

Shaun M


Re: tek 2215 trace position issues

nanovnauser@...
 

Well i hooked up the eht to the crt and moved the whole lot to one side,heres a few readings i took,on q387 base i get 8.8v,it should be 2.6!,r290 wiper measures as follows,fully cw=3.44,fully ccw 3.4v,r190 is fully cw3.4,fully ccw 3.4v,dont know if this helps?


Re: 465B recapping and tantalum caps

n4buq
 

Hi Dave,

I think the subject has come up and I _think_ the filter sections for both are the same - or at least with very little changes but I can't really be sure.

Send me your address and I'll get a board out to you if you still want one. You can send me a couple of bucks to cover costs if you want but not a big deal.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "David Austerman" <737builder@...>
To: "tekscopes" <TekScopes@groups.io>
Sent: Sunday, October 24, 2021 4:49:48 PM
Subject: Re: [TekScopes] 465B recapping and tantalum caps
Barry-
I haven't looked and compared 465 and 465B board layouts on the prints, but I
figure you might have been down the road before of being asked if these are
compatible with a 465? If so, how would I obtain one of these? Do you have a
website? I have a 465 that is working fine with original electros right now
anyway, but you know how that goes. I'd like to maybe get ahead of the problem,
or at the very least be ready if I put it off until that fateful day. I might
actually not procrastinate if I had a nice little board!
Thanks, dave austerman KG5IPO



Re: 465B recapping and tantalum caps

David Austerman
 

Barry-
I haven't looked and compared 465 and 465B board layouts on the prints, but I figure you might have been down the road before of being asked if these are compatible with a 465? If so, how would I obtain one of these? Do you have a website? I have a 465 that is working fine with original electros right now anyway, but you know how that goes. I'd like to maybe get ahead of the problem, or at the very least be ready if I put it off until that fateful day. I might actually not procrastinate if I had a nice little board!
Thanks, dave austerman KG5IPO


Re: FS: 7000 series (parts) plugins 7A18 (X2) 7B53A and 067-0657 Calibration Fixture

Oz-in-DFW
 

All plugins have been spoken for. I'll relist anything that falls through.

Thanks, and sorry for any confusion I caused by missing posted replies.

--
Oz (in DFW, Texas USA) N1OZ


Re: TDS3012 and up

John Gord
 

The main boards for the TDS30xx 4 channel units are different from the 2 channel units. I don't think there is any (practical) way to convert a TDS3012 to a TDS3014 without a total main board transplant.
--John Gord

On Thu, Oct 21, 2021 at 02:27 PM, <durechenew@...> wrote:


Gentlemen,
I while back I informed here that I'm trying to revive a TDS3012; essentially
that was done with good results.
That scope came to me with Rack Mount RM3000 (includes all the hardware to
install the scope) that doesn't have room (or usage) in my 'lab' (let's call
it that); it's in fairly good shape and if someone has a need for it, can have
it for postage (that might mean something, I'm in Toronto, Ontario, Canada).

The main subject is different: assuming there would be available another
TDS3012, what would be the challenges (from electronic point of view -
disregard mechanical stuff), to convert to a TDS3014? I believe HÃ¥kan is one
of the people with a lot of info and knowledge about these scopes and I'd love
to hear his opinion. Anyone else interested or with knowledge is invited to
share opinion; I believe is doable.
All the best to all
TT


Re: TM500 tester switch - Attn. Jared Cabot.

Shaun M
 

Colin,

I purchased the parts for this project from Mouser in January of this year. The Grayhill switch we are discussing arrived packed a plastic tube and included the pins, stickers and paper instructions for configuring it.

Shaun M


Re: TM500 tester switch - Attn. Jared Cabot.

Colin Herbert
 

Has anyone else had this problem with switches from DigiKey, or am I alone?
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Colin
Herbert via groups.io
Sent: 23 October 2021 15:38
To: TekScopes@groups.io
Subject: [TekScopes] TM500 tester switch - Attn. Jared Cabot.

Hi Jared,

I have now (eventually) got what all of the parts for this tester seem to
be. I am however a bit puzzled about the Grayhill switch. Mine doesn't seem
to have anything other than the switch, internal tooth lockwasher and
mounting nut present. I see that you used a set of limiter pins and a foil
sticker to retain them, but these items do not appear with my switch. Such
pins and sticker do not appear on the DigiKey list either, as far as I can
see. Did you actually use the proper Grayhill items and do DigiKey stock
them? If not, how might I go about getting the switch to correctly be a
4-pole, 6-turn switch?

Colin.


Re: TDS3044B repair

 

You posted that message in a thread with a different name: "TDS3012 and up".
That's unnecessarily confusing.
Your question was about converting a two-channel TDS3012 to a 4-channel version (TDS3014). I can imagine that not a lot of people would be able to answer such a question, knowing that precious little is known about these 'scopes technically, both hardware- and firmware-wise.

Raymond


Re: TDS3044B repair

durechenew@...
 

I posted a message (it is actually a new post, #187365), that, for unknown reasons, was not broadcasted (or nobody had a reason to answer or comment); thought to mention it here, maybe it's still of some interest to someone or there are some people that would like to know more on the subject; or have info to share (I'm sure about that).
Regards
TT

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