just bought a HP 1720A and have some issues??

[getaremotestart]

First H'i, my name is Josh and I'm new here!! Anyway I just picked up a HP 1720A Oscilloscope off of ebay for 100.00 dollars!! Looks like it was for military use at one time!! But first off when I plug it in it does power on with out an issue and the cry heats up pretty quick about 15 to 20 seconds and it's ready to go but it displays the trace vertically instead of horizontally!! First issue second issue is I can't seem to get it to trigger internally or externally the sweep generator seems to work as the led that represents it turns on and off at specific times also can't get it to show a waveform!! It will display a trace on both channels with a audio signal as input but it won't display the waveform almost like something may be wrong with the time div but it acts the same on both channels!! Also the little green light flickers under the scale illum control pot but it's not an led I think it's just a normal filament type bulb!! It didn't come with the service manuals or anything!! Also bought new probes as it didn't come with them either!!! Also took the top cover off just to look for anything obvious like disconnected wires or burned components!! I found 2 wires running from the crt to a circuit board but they were disconnected and there's a pair conning off the larger circuit board on the right side of the crt but they have metal connectors on the ends also there's two the same colors wires coming off of the crt tube that are pretty much identical to the 2 coming from the board and again have these metal terminals on the ends but are both same gender!! There all female connectors so I'm wondering if maybe I'm missing a board?? Or if it was just an option that this scope doesn't have!! Colors are green for 1 and white for the other!! I do service manuals on the way but wanted to see what you pro's thought might be going on here!! Yes I've had scope completely unplugged from household power while sticking my hands in it LoL!!! I'm new to scopes but am fairly handy and know more than most about electricity but no means do I consider myself an expert!! Bought it for adjusting gains etc on car stereo systems and possibly down the road get into amp and automotive sensor diagnosing!!

 

[Inquisitive]

Got this on the way?

https://bama.edebris.com/manuals/hp/1740a/

 

[KeepItSimpleStupid]

There is an HP Yahoo group that you could join and get more help. Your sentences are a bit run-on.

 

[Tony Stewart]

Rotate yoke 90 deg to get sweep in correct axis. Then you have a 50/50 chance of getting it right. or wrong

Ensure trigger channel is same as signal and adjust trigger level near zero crossing.
See A or B near vertical and don't choose Line input unless you want 50/60 Hz trigger.

 

[KeepItSimpleStupid]

The scope might not even have a yoke, just deflection plates. You can swap them too.

 

[ronsimpson]

Rotate yoke 90 deg to get sweep in correct axis.

??? Should not have a yoke.???

 

[Tony Stewart]

CRT's had a yoke defelection with 20MHz BW and then used solid-state drivers for electrostatic deflection in zones up to 100MHz BW in the mid 70's for character writing on displays.

You may be correct, Ron as some of the later HP17xx series introduced a transmission line based CRT with >=100MHz BW, which may or may not have as equal BW in both XY axes, so for RADAR detection, they may have rotated the axis for preferred slew rate in the X or Y axis.

 

[gearhead63]

I have a 1720A and another HP scope that had problems, I pulled the PCB's that the time/div knobs go to on the right side
and cleaned the contacts and board surfaces. They used some kind of grease to lube it and it gunked up.
I also found bad corroded capacitor on one of the boards.
Once clean they both worked perfectly. I also still have 2 parts scopes sitting on my shelf if you may need some parts.

 

[gerar2016]

Hi gearhead63. I have a HP 1725A with missing board.The board is PN 01720-66547 (Delayed Sweep). This board is the same for models
1720/22/25/27.
If you have one , are selling it?
Please try to check.
Thank you so so much.

 

[gearhead63]

Hi gearhead63. I have a HP 1725A with missing board.The board is PN 01720-66547 (Delayed Sweep). This board is the same for models
1720/22/25/27.
If you have one , are selling it?
Please try to check.
Thank you so so much.

I don't have my parts scopes at my shop at the moment, but I will take a look asap. May be middle of week before I can get them here. I,ll post what I have as soon as I can.

 

[gerar2016]

Thank you so much. I will wait your kind reply. May be i finally can have my scope fully operative.

 

[gerar2016]

Hi again Gearhead63. Some news about HP boards?
Sorry for ask.
Thanks

 

[gearhead63]

Sorry, I haven't been able to go get those scopes. They're at a friend's house. May be able to get them tomorrow.

 

[gerar2016]

Thank you so so much .