Some years ago I bought an old Telequipment DM64 oscilloscope. It
worked, but the time base was about 20% off (a 50Hz Signal looked like
40Hz). I didn't use it for some years. When I switched it on some days
ago, the horizontal deflection did not work anymore (it didn't sweep
from left to right, just a point (without signal) or vertical line
(with signal) on the screen).

I have never repaired a scope before. Any tips on how to proceed? Could
it be, that the electrolytic capacitors just have to be replaced
(because they dried out)? Do non-electrolytic capacitors also die of
old age? Or any other component?

Thanks for any help

Tolux

tolux wrote in message
oups.com...
Some years ago I bought an old Telequipment DM64 oscilloscope. It
worked, but the time base was about 20% off (a 50Hz Signal looked like
40Hz). I didn't use it for some years. When I switched it on some days
ago, the horizontal deflection did not work anymore (it didn't sweep
from left to right, just a point (without signal) or vertical line
(with signal) on the screen).

I have never repaired a scope before. Any tips on how to proceed? Could
it be, that the electrolytic capacitors just have to be replaced
(because they dried out)? Do non-electrolytic capacitors also die of
old age? Or any other component?

Thanks for any help

Tolux


You may find something relevant/similar in the scopes section of my repair
briefs file
http://www.divdev.fsnet.co.uk/repair4.htm


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

On 9 Nov 2006 00:55:09 -0800, "tolux" wrote:

I have never repaired a scope before.

There's nothing special about a scope.

Any tips on how to proceed?

Do a real thorough web search for a schematic or try to buy
one. This will save you most of the time you otherwise spend
guessing in front of the opened unit.

As you see a dot, the high voltage seems to be present and
the crt seems to be ok.
Before going into it, train the switches by operating them several
times to see wether one doesn't give contact.
Then inside, test the Y-amplifier, see wether the last stage
of the X-amp gets the sawtooth and go from there on.

Beware the high voltages! Good luck,
H.

tolux wrote in message
oups.com...
Some years ago I bought an old Telequipment DM64 oscilloscope. It
worked, but the time base was about 20% off (a 50Hz Signal looked like
40Hz). I didn't use it for some years. When I switched it on some days
ago, the horizontal deflection did not work anymore (it didn't sweep
from left to right, just a point (without signal) or vertical line
(with signal) on the screen).

I have never repaired a scope before. Any tips on how to proceed? Could
it be, that the electrolytic capacitors just have to be replaced
(because they dried out)? Do non-electrolytic capacitors also die of
old age? Or any other component?

Thanks for any help

Tolux


If you care to email me on the address outlined on URL below I have a
service manual with schematics for that scope, not to whatever apparent
email address this posting may show.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

tolux wrote in message
oups.com...
Some years ago I bought an old Telequipment DM64 oscilloscope. It
worked, but the time base was about 20% off (a 50Hz Signal looked like
40Hz). I didn't use it for some years. When I switched it on some days
ago, the horizontal deflection did not work anymore (it didn't sweep
from left to right, just a point (without signal) or vertical line
(with signal) on the screen).

I have never repaired a scope before. Any tips on how to proceed? Could
it be, that the electrolytic capacitors just have to be replaced
(because they dried out)? Do non-electrolytic capacitors also die of
old age? Or any other component?

Thanks for any help

Tolux


As a point of interest the M of DM64 means alalog memory as used in early
computers. I've never seen one but apparently it is possible to have a fault
condition with the retention voltages inside such CRTs that lead to random
discharges giving a glorious internal fireworks display. Anyone seen such in
person ?

As someone said, as you have a dot , you are probably onto a winner

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

In article , "N Cook" wrote:
tolux wrote in message
roups.com...
Some years ago I bought an old Telequipment DM64 oscilloscope. It
worked, but the time base was about 20% off (a 50Hz Signal looked like
40Hz). I didn't use it for some years. When I switched it on some days
ago, the horizontal deflection did not work anymore (it didn't sweep
from left to right, just a point (without signal) or vertical line
(with signal) on the screen).

I have never repaired a scope before. Any tips on how to proceed? Could
it be, that the electrolytic capacitors just have to be replaced
(because they dried out)? Do non-electrolytic capacitors also die of
old age? Or any other component?

Thanks for any help

Tolux


I forget what model I had. Similar problems. It was a monster. I gave up.
I was glad to ditch it.I did get it to work, but the calibration was off.

greg




As a point of interest the M of DM64 means alalog memory as used in early
computers. I've never seen one but apparently it is possible to have a fault
condition with the retention voltages inside such CRTs that lead to random
discharges giving a glorious internal fireworks display. Anyone seen such in
person ?

As someone said, as you have a dot , you are probably onto a winner