Oscilloscope

[Andy Burns]

I must admit I started out looking at second hand ones on eBay, then USB ones and kept talking my self up from there ;-)

[tabbypurr]

the basic banggood one has similar specs too. IIRC for about £25 you can get a lot more bandwidth.

CRTs respond very well to a little heater voltage increase. Never zap them, it ruins tubes.

NT

[Brian Gaff]

EHT capacitors? Brian

[Dan S. MacAbre]

I've no idea how useful this sort of thing is, but I thought I'd throw it out there

[RayL12]

I believe I had the same 'dual-scope' model? The unit has a very handy feature which is, the expected signal voltage at most points on the boards. Makes fault finding so much easier.

...Ray.

[Another Dave]

Oscilloscope software like this has been available on Windows and Linux for donkey's years. It's fine if you just want audio frequencies. I've used it successfully to diagnose a radio-control aircraft receiver. The pulses weren't very square, but they might not have been in the first place. You need to be careful about the voltage divider so you don't fry your sound card's mic input though.

is one such but there are many more.

Another Dave

[Geo]

Focus at one end - check the high value resitors either side of the pot. They often shift out of tolerance. Brightness pot may be affected as usually in the same chain.

[jkn]

It's a Tek 465 (B, I think), so not as bad as that by any means.

North Pennines, hmm. I am on the South Coast so carrier costs might make it not worthwhile. I am likely to be up in Preston a little over the next few months if that helps any?

jon N

[Dave Liquorice]

hopefuly

Thanks for that, will check it out, yes the brightness is in the same chain.

I've got it working after a bit of wild goose chasing due to not being familiar with the normal operating voltages on valves. I now know that 0 to 2 V grid voltage is not enough, even if it does track the X Shift control. During fiddling the wire for the X Shift wiper disconnected itself from the PC post with a nice cystaline fracture look to the end. Must have been high resistance before becoming open circuit. Replaced wires to pot and X shift now gives 0 - 50 V grid and things are happpy.

Well happyish, after a few hours the transformer started to make gentle frying noises, smell and be rather hot. Nothing else was overly hot. Electrically leaking electrolytics would run hot wouldn't they?

[tabbypurr]

Just depends how leaky they are. Often not.

NT

[whisky-dave]

Well we just brought one of these. £96

scilloscope.html

Seems fine for what it is and it has a built in sig gen. Handy to lend to student doing audio projects. max 80V pk-pk

[Dave Plowman (News)]

Dave would likely be familiar with that one, as it's the one I have. Much used in broadcasting at one time. And they frequently were trolley mounted.

[tabbypurr]

-oscilloscope.html

Specs look like the banggood £15 one, but you do get a case :)

NT

[Dave Liquorice]

wouldn't

Having let it cool down overnight I powered it up again this morning. Started to make noises within 10 mins, brightness faded and display became pin chusion / barrel distorted. Transformer hot and blank bit of PCB that has a double 0.25uF 1500 VDC smoothing capacitor for the

-1000 V rail behind it was warm...

Have you looked at the price of 0.25uF 1500 VDC capacitors? First hits I got where £50 each. NOS on ebay from the eastern block countries are around USD30....

My inexpert eye cast over the datasheet tells me that a couple of these might survive the ripple.

9460

0.22uf 1600 VDC £4.35 each but digikey want £12.00 shipping, mouser cheaper but £12 shipping again. Element 14 £10 each plus shipping from across the pond...

[Dave Liquorice]

Interesting the Osciprime Legacy runs on my tablet but I don't know if the tablet has a 4 pole headphone socket to get a signal into it, play time...

[whisky-dave]

ge-oscilloscope.html

and you don't have to worry about how to solder the SMD chip, or worry abou t getting it working.

[The Natural Philosopher]

Blimey. I used to use those things and they were around 60p each.

here ya go. £2.69 each and nice polypropylenes

|pcrid|78108377949|&CAWELAID=120173390001549446

[Clive George]

760v on a 1000v rail?

[Bill Taylor]

760 VAC, 1500 VDC

[The Natural Philosopher]

1500V DC. 760v AC

Download the data sheet.