Telequipment D53

[Bushbaby]

Hi All,
It appears that I have the opposite problem to John (Geaney) in that my scope appears to be working well in the x sweep but not the y?? I can alter the controls but it doesn't seem to make any difference whatsoever.
Unless this is a quick fix it will certainly have to go the rear of the 'to do' pile!

Regards

Rob

[Skywave]

Hi Rob,

Do the vertical shift controls work?
Do you get no vertical displacement of the trace for all settings of the input attenuators?

From memory, that 'scope isn't that complicated. I'd try checking out the PSU section first: there may well be a 'quick fix' thereat waiting for you!

Al.

[Yorkie]

Don't know if you've got the manual for it Rob, but if not, you can download it from here:

http://www.thevalvepage.com/download/dow...e=d53a.pdf&dir=telequipment

[Bushbaby]

Hi Al/David,
Yes, I do have the manual for it but strangely it burst into life last night and started working to my amazement. The only thing that I have yet to figure out is that it shows the second channel as a flat baseline if not in use which is a bit annoying and I haven't figured how to switch it off if using but one channel

Regards

Rob

[Skywave]

If the second Y-input channel is only showing a horizontal line - but you can shift that horizontal line up and down the screen with its vertical shift control, and that when a signal is presented to that Y-input, you get the resultant waveform displayed - then that is normal behaviour. If the undeflected trace arising from no input to that Y-input is distracting, then use its vertical shift to move it off the screen.

As for it now "bursting into life", that suggests one of 4 things:
1. Dry solder joint; fix = obvious.
2. Intermittent / dirty mechanical contact somewhere: fix = scrape & clean + switch cleaner. Check all plugs & sockets.
3. Dirty switch somewhere: the T/B switch or trigger selector being favourites: fix = switch cleaner.
4. Something else I've forgotten to mention: but I'm sure someone else will!

I wouldn't ignore that fault, hoping that it will never re-occur: it will! Although I do appreciate that tracking down intermittent faults can be very time-consuming and frustrating.

Al.

[Bushbaby]

Hi Al,
Thanks for your valued reply. I would think that the 'scope hasn't had much use in recent years and could do with a wee bit of a service. The display now its working is really sharp suggesting that this will be a nice 'scope to use. i think I need to get to grips with the plug in modules as the type CD amplifier module appears a bit strange to use. I wonder if I can pick up other modules for this?

Regards

Rob

[Skywave]

Hi Rob.
First, let me say that I am not totally familiar with that particular 'scope: all my comments are of a generic nature, based on the general principles of 'scope design, operation - and my general experience. But I notice your reference to 'plug-in modules'. Now bearing in mind your earlier fault report and your comment about lack of use of this 'scope, and knowing how contact surfaces of the 'wipe-to-connect' plug 'n' socket style of connector become easily tarnished with lack of use, I now suspect that that is where the original fault was / is. Very briefly, the contact areas should always be bright 'n' shiny. Often several 'plug-in' / 'plug out' operations scrape sufficient tarnish away to produce a sufficient low-resistance contact on the pins. (Same argument applies to rotary switches and valve pins and their sockets). Bear in mind that the currents across the plug/socket connectors will usually be very low - and typically only of the order of a few mA in the case of PSU currents; far, far less for signal currents. A little bit of tarnish can easily introduce sufficient resistance to stop things working . . . and maybe intermittently . . .

As with all electronic products, provided the basic electronic design is 'sensible' and quality components have been used, it is then often the 'mechanics' that cause trouble - especially if dampness, humidity, wide ranges of temperature have been manifest.

Al.

[Shaman]

Hi Rob, have a look on this link, i think you will find your scope details, http://www.thevalvepage.com/servdata/tes...lequip.htm
if it has an intermittant fault this needs finding and fixing to save more trouble later ......regards.....Alan.

[Michaelr]

Rob,

I agree with "Skywave". Quite often with kit like this aside from capacitors etc oxidation on swich contacts and plug in contacts cn cause failure.

Keep the unit in a nice warm room for a few weeks to dry out and use that Deoxit you bought for cleaning switches and plugin contacts. Get the unit stable before looking for obscure faults. It sounds to me that you have a good unit there once it is completely dried out and used.

Have you got to grips with your sig gen yet

Mike

[Bushbaby]

Hi Mike,
Kev bought the Deoxit not I. However, Al's comments have made me think about the contacts being tarnished which I shall have a look at. I still haven't looked at signal gen (I can't think why not?) so now i have tidied the garage I shall break my back lifting it onto the bench and give it a try this weekend.

Regards

rob