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Re: 2235 display problem

Chuck Harris
 

Put the scope in X-Y mode, with no input signal, and
measure each vertical deflection output to ground.

They should be about the same voltage. If one is at
zero, or the supply voltage, that driver is burned out.

A very common problem that often comes from shorting
one output to ground.

-Chuck Harris

Pmccandless via Groups.Io wrote:

Beamfinder is working properly. When pressed, the display compresses to a single position on the x-axis, but the amplitude remains. Here is a helpful hint...I pulled (disconnected) the upper and lower plate deflector wires from the CRT and turned the unit on again... without any vertical input connected, the CRT display was exactly the same as before...just a big rectangle-appearing image at all sweep speeds. This tells me that something is amiss in the CRT or associated electronics. Still scratching my head on this one.

Phil




2019 Sphere Stuff Day event preview

walter shawlee
 

those of you that have come to one of our previous stuff day events know that there is a great mix of free and cheap electronic "stuff" for everybody to snorkel through. it is a true BYOB (bring your own boxes) affair. usually we get rid of at least 2 tons of gear at each event.

This year will be a bit different, as both susan and I are turning 70, and we need to totally clear out at least one of our off-site storage units (about 5 tons). We will be running the event for a full week, to fit as many of your schedules as we can, and whole bankers boxes of stock will go for just a few bucks. Boxes filled with new fans, terminal blocks, pots, tek and hp spares, breakers, switches, LEDS, displays, pots, power resistors, capacitors, motors, smd parts, transformers and CRTs. We have at least 50 CRTs that really need to go, to make some space. Also about 100,000 primo Osram SMD LEDs, new in reels.

There will also be a huge pile of Tek, HP, Fluke, Boonton and other test gear and parts to go. Susan wants at least half of the stuff cleared out of rooms, aisles, our sauna, and storage, so this will really work to your benefit.

We are located 4 hours NE of Vancouver in BC, close to Washington, Oregon and Alberta by highway. We are happy to put up guests overnight if the room is free, and we are looking for "best dates" for the event. To some degree, it is linked to weather, best with no rain for a week before, and clear highways. Usually it is within 2 weeks of the Easter long weekend. You can get more details from our website at:


Our goal is to clear out all the bulky stuff, gear we are never going to get around to fixing, and extra stock that should really be home with somebody else! No, Sphere is not closing, but we REALLY need to clear out many things that nobody even knows we have.

please feel free to email off list with any special requests (walter2 -at- sphere.bc.ca), and let us know if you can come up in 2019!

all the best,
walter
sphere research corp.


Re: 466 Channel 2 problem

 

I have had another snoop around with my multi-meter and I find that test-points 4 and 7 on channel 1 both show +5.7V, the equivalent ones on channel 2 show +3.37V (TP 11) and +7.31V
(TP 14). What does this show, I wonder?
Colin.

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Colin Herbert via Groups.Io
Sent: 08 December 2018 14:42
To: [email protected]
Subject: [TekScopes] 466 Channel 2 problem

Hi,

I have been faffing about with a 466 with a channel 2 problem for a few weeks, and though I might eventually sort it, I thought I would consult the experts and possibly save a bit of time.

The scope came with a non-operational delayed time-base and an intermittent graticule illumination light. I have fixed both of these now, but the channel 2 problem is bugging me. The scope works on channel 1 alone fine, so it can't be anything after the diode-switching circuitry (can it?), but channel 2 doesn't display normally. If I push the beam-finder switch, I see channel 2, but the position control does nothing. If I use a slow time-base setting and switch to "alternate", I can see channel 1 and there is a period when channel 2 would be displayed, but no channel 2 shows. I have checked voltages and signals for channel 2 from the end of the attenuator through to the diode channel switching (possibly not comprehensively) and mostly cannot see anything untoward. I have also checked to see that the "position" control does change the voltages on the two nominal +2.8V rails, but rather asymmetrically (-0.6 to +2.8V on one rail and 2.79 to 2.8V on the other). I am suspecting that there is something wrong with the "position" control circuitry, but changing Q262 didn't solve the problem.

I also noted that I cannot trigger the time-base from channel 2.

Am I missing something obvious? I would like to get this 466 working, as it is one of three that I have, one of which has already become a parts-donor. I might even try fixing the other one sometime.
TIA, Colin.


Re: How Many Scopes?

Craig Sawyers
 

Dual amplifier in left and right vertical (set to chop or alternate) and dual timebase (such as a
7B92A) in each horizontal compartment.

Select vertical mode beam 1 right, beam 2 left.

Set horizontal mode to beam 1 right, beam 2 left

Set each 7B92A to intensified and delayed sweep ,and set trace separations to suit.

Gives a total of 16 traces.

Craig

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of TomC
Sent: 08 December 2018 18:39
To: [email protected]
Subject: Re: [TekScopes] How Many Scopes?

On 12/7/2018 3:15 PM, Craig Sawyers wrote:
Now just what do I do if I have to display more than 12 waveforms at once ?
Ah - you can do that with a single 7844
How?


Re: 2235 display problem

 

Beamfinder is working properly. When pressed, the display compresses to a single position on the x-axis, but the amplitude remains. Here is a helpful hint...I pulled (disconnected) the upper and lower plate deflector wires from the CRT and turned the unit on again... without any vertical input connected, the CRT display was exactly the same as before...just a big rectangle-appearing image at all sweep speeds. This tells me that something is amiss in the CRT or associated electronics. Still scratching my head on this one.

Phil


Re: What have i here ? (Tek TDS 540 )

 

On 12/8/2018 3:26 PM, mattko87 wrote:
I has a TDS540, scussefully repaired.
But, few interessing notice: ACQ-Board has a masked programmed ?C from Motorola. it is writed from Motorola with "prototype"
2x Serial-Label : B010197 and VER2.
What is meaning VER2 ?
Hello, Matt--
As a guess... VER2 = version 2

73--

Brad AA1IP


What have i here ? (Tek TDS 540 )

 

I has a TDS540, scussefully repaired.


But, few interessing notice: ACQ-Board has a masked programmed ?C from Motorola. it is writed from Motorola with "prototype"
2x Serial-Label : B010197 and VER2.

What is meaning VER2 ?

Thanks
Matt


Re: How Many Scopes?

 

Hi all?I for one have more scopes than i can or will ever use , but for some strange reason i keep getting them . For me it just fixing them that i enjoy and once fixed it goes in the pile that i have , speaking of pile i am looking for one last tek to complete my dual beam collection,? 7844 is the last tek needed for dual beam collection,? if anyone has one reasonable please let me know,? thanks and keep the hobby going .
On Sat, Dec 8, 2018 at 1:39 PM, TomC<tomc@...> wrote: On 12/7/2018 3:15 PM, Craig Sawyers wrote:
Now just what do I do if I have to display more than 12 waveforms at once ?
Ah - you can do that with a single 7844
How?


Re: How Many Scopes?

 

On 12/7/2018 3:15 PM, Craig Sawyers wrote:
Now just what do I do if I have to display more than 12 waveforms at once ?
Ah - you can do that with a single 7844
How?


Re: How Many Scopes?

 

On 12/7/2018 2:04 PM, Vincent Trouilliez wrote:

I guess it's like asking a women why does she have 564 different pairs of shoes, but only one pair of feet to use them with....
Most men will know that is a question best not asked.


My scopes:

2232, 2246
2445, 2465
7704, 7844, 7854, 7904
TDS210


Re: Viewing hood part number for 7000 series scopes

 

John: I received the viewing hood today. Looks great. Thank you. I will send a check off to you today December 8 2018.

Gary


Re: Tek 371 test fixture

 

Hi Bob??Thanks for your reply that you sent to me with pictures I would like to ask you if you could possibly let me know the gauge of the wires there and the possible length of the cord coming from the plug that goes to the Tracer to the test fixture. Once again thank you Neil
On Sun, Nov 4, 2018 at 6:07 PM, Bob Koller via Groups.Io<testtech@...> wrote: Oliver,

I have uploaded some pictures to the Photos section.
A few notes:
The fixture pictured is missing the clear safety cover.
There are three microswitches in the fixture; two in front that are actuated when the cover is closed, and one at the hinge that is actuated when the cover is open.
There is a? 10nf cap connected as shown in the main housing.
The resistor shown in the removable section is 1k.
There is a schematic in the 371A service manual available at Tek.co, and on the Tek wiki.


Re: Probe bags ...

 

On Sat, Dec 8, 2018 at 6:07 AM David Slipper <softfoot@...> wrote:
Has anyone come across a source of probe/manual bags - or a workable
alternative ??
I'd say you've found the best source already. A lot of us use our
scopes on the bench, and take the probe pouches off so we can stack
things on top of the scope. So, post your requirements here.


Re: Capacitor sniffing

 

My experience with failing capacitor is the strong smell of raw fish. Sometimes I can smell it as soon as the unit arrives or definitely during case removal. I don¡¯t think I¡¯ve noticed a soap/perfume smell.

Craig


Re: A cautionary tale ...

 

Mine actually has 3 in that position - I had assumed that was their
purpose - thanks for the warning, though.

Dave

On 08/12/2018 13:56, george edmonds via Groups.Io wrote:
Hi Dave
Although it is difficult to know where your "spare" screw came from
please make sure that the rear right hand side case screw ?is present,
it is part of the power supply heat sink path and is frequently missing.
73 George G6HIG

On Saturday, December 8, 2018 12:57 PM, David Slipper
<softfoot@...> wrote:

I have acquired a Tek 2225 as a 50MHz analogue alternative to my TDS744A
but before I powered it on I took the case off to make sure nothing had
shaken loose in transit (I make that a policy for mains powered stuff).

Everything was OK but I did find a loose screw rolling around in the PSU
area !!!

I am very glad I gave the thing a "once-over" or I would have allowed
the "magic smoke" to escape !!!

I seem to remember someone else finding loose screws.

One place I worked always played an air line around the kit before
putting the covers on looking for surplus/dropped screws and other
rubbish.

BTW I'm very pleased with the 2225, works nicely and is a bit more
portable than the 744A.? I'd have preferred a 2235, but I may get one of
those as well - just don't tell the wife !!! ;-)

Now at 5 and counting ;-)

Dave










.


Re: Probe bags ...

 

Yes, that may work with the application of some self-adhesive Velcro.

Dave

On 08/12/2018 15:28, Richard Solomon wrote:
How about heavy duty, large
Zip Lock bags ?

73, Dick, W1KSZ


Re: Smashed CRT on a 2215 - where to find a substitue?

 

If there were an included thread to even SKIM 8^(

On 12/8/2018 10:40 AM, Carsten Bormann wrote:
On Dec 8, 2018, at 16:17, Carsten Bormann via Groups.Io <cabocabo@...> wrote:
Well he did give it away, no?
(No, he didn¡¯t. That¡¯s what you get for replying after just skimming a thread. Promise to better myself.)

Gr¨¹?e, Carsten



--
Dave
Manuals@...
www.ArtekManuals.com


Re: TDS3032 does not boot. LCD backl-ight and fan working.

 

Thanks Dave.
I suspected that a bad NVRAM will let the scope at least get as far as the DPO splash screen.

I guess I have a deeper problem.

Can anybody else suggest where I should look?


Re: Smashed CRT on a 2215 - where to find a substitue?

 

On Dec 8, 2018, at 16:17, Carsten Bormann via Groups.Io <cabocabo@...> wrote:

Well he did give it away, no?
(No, he didn¡¯t. That¡¯s what you get for replying after just skimming a thread. Promise to better myself.)

Gr¨¹?e, Carsten


Capacitor sniffing

 

Old devices often have a characteristic smell, e.g., from the dust that is being cooked inside the device.

Some of this smell unfortunately stems from leaking capacitors.

Is there a guide somewhere that allows mapping a specific smell to a specific kind of capacitor?
I know we don¡¯t have smell-o-vision in the Internet, but it should still be possible to verbally describe smells.

I¡¯m asking because I have an FG501A with some performance problems, as well as a characteristic smell.
Soapy, perfumy, I¡¯d say. I don¡¯t ¡°see¡± which capacitors are leaking, so I would love to use the smell to point to potential culprits.

(Of course, the performance problems could be unrelated to the smell, and the smell could also come from other components cooking themselves. In any case, it would also be nice to know how toxic that smell is¡­)

Gr¨¹?e, Carsten