Anyone near Rotherham who could test my Scope?

1*transistor*1 said:

hi,

i used to have a scopex oscilloscope but one day i switched it on and the crt exploded!!
so i wouldnt be surprised if it fails but good luck: hope it works.

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bigal_scorpio said:

Here'e my scope service manual, or for anyone with a Scopex 14d-10(v)


i used to have a scopex oscilloscope but one day i switched it on and the crt exploded!!
so i wouldnt be surprised if it fails but good luck: hope it works.

Click to expand...

bigal_scorpio said:

Hi to all,

Thanks for all the info past, present and future guys. You have got me through some difficult problems!

After following a link from kchriste about Oscilloscopes I am beginning to think mine may be faulty. Its an old one that I acquired and never had instructions or specs for.

To be honest I cant even follow basic "How To" guides as my scope and the tutors never seem to have the same controls or parts!

E.G. in one guide it mentions the probe test that gives a square wave output, I have a test probe point but I cannot get a square wave from it, just a constant 4v trace!

Also I have never managed to get anything from the "A probe" and can even only get a test signal on "B" but I do get wild traces when touching the probes with fingers.

What I need is someone with scope expertise to check mine and maybe just get me going with what means what with my seemingly unusual scope (Scopex 140-10V). I would be quite happy to travel a reasonable distance if anyone is willing to help and show me the ropes or condemn my scope!

I live in Rotherham, close to the Meadowhall shopping center and M1.

If anyone can help please let me know. I am sure Eric Gibbs would help me as he has done with advice many times in the past but sadly he lives hundreds of miles away from me, maybe I should consider flitting closer hehehe, but seriously any help will be greatly appreciated.

Thanks for reading my plea................Al[/hi,

i used to have a scopex oscilloscope but one day i switched it on and the crt exploded!!
so i wouldnt be surprised if it fails but good luck: hope it works.]

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bigal_scorpio said:

Hi Eric,

Results as follows:-

1 = -1v3
2 = +5v6
3 = +15v1
4 = +15v1
5 = +15v1
6 = +180v
7 = +180v
8 = +14v4 measured on collector
9 = +14v4 measured on collector
10 = -15v1 one end 0v other end
10a = 15v1 both ends

I am not an expert by any means, but I have noticed that one of the +15v1 seems to be -15v1 on the drawing is this an error or a fault on board?

Hoping these will help solve my problem...........Al

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bigal_scorpio said:

Hi Eric,

On the drawing you just posted the TR152 and TR153 seem to be duplicated lower down, well I nthink it says TR153 its a bit blurred, but there are definately 2 TR152s shown on the drawing!

This is baffling me as there is only one FET granted its a dual one but the drawing shows 4 connections to what I can only assume is 1 dual FET, how does this work? Is mine missing a dual fet?

Is it worth me listing my FETs to see if any will do as subs?

Al

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ericgibbs said:

hi,
I'll have a closer look at the photo's.

Have you had chance to remove the pair of wires from the 'top' 733 [M151] and ground the two pins to 0V.
Just do it for the top amp at the moment.

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bigal_scorpio said:

Hi eric,

Was just about to do it, do you mean the top 2 wires in the photo you sent?

Al

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bigal_scorpio said:

Hi Eric,

On the drawing you just posted the TR152 and TR153 seem to be duplicated lower down, well I nthink it says TR153 its a bit blurred, but there are definately 2 TR152s shown on the drawing!
Al

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ericgibbs said:

hi,
Its most likely me misreading the blurred dwg.

Iv'e rechecked the U421 pdf, which I understand is the metal case equivalent of the E421, its got 6 wires for sure.

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bigal_scorpio said:

Hi Eric, mine says U441 on it and this comes up as a dual Fet, heres the sheet

Maybe they are more easily obtainable or possibly I may have a couple of single Fets that I could use, this would be best as I could do it now!

Regards................Al

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ericgibbs said:

hi,
I'll look thru it.

The test you doing at the moment, with the wires off, will tell us if the M151 [733] is OK.

Once we have established that, we will move on to the source follower FET.

My aim is to get at least one channel fully working with sync, so that you can use the scope. Then we can look at the other channel.OK.

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bigal_scorpio said:

Hi Eric,

The 733 now measures -1v5 on pin 7 and +6v4 on pin 8. Wires off and pins grounded.

Does this tell you something?

Al

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Looks like I will be tryig to find a 733 now then aswell!

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bigal_scorpio said:

Good morning Eric,

I do think I have a faulty 733!

The 733 now measures -1v5 on pin 7 and +6v4 on pin 8. Wires off and pins grounded whichever socket its in!
I assume the 'other' LM733 gives the correct output voltage.???

Putting them on headers would be no problem, not after making the adaptors for the CAs anyway See attachment, not pretty but functional!

The NE592 is a DIP direct replacement, no header required.
I'll post them Monday 25th. OK.

I have been trying to find other sources for the U441 while I was doing nothing and found one on ebay, have a look, is that for 1?
Thats expensive for one!.
If you plan to use the scope for some years, I would buy at least 3 from the web.

**broken link removed**

And whats with the postage, he is in England, not the USA!

Makes the link you sent me look cheap mate, think I will send for one from there.

Anyway thanks again Eric and fingers crossed I will eventually get a working scope

Regards..............Al

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