HP 1742A Oscilloscope differences

[gezza123]

Hi Guys
I am looking for a user/service manual for a HP 1742A Oscilloscope.The only problem is that I have got a circuit range from 1740 to 1742a, and they are different to the Oscilloscope that I have.The Oscilloscope has a printed model No. 1742a but the circuit and layout are different, in that mine has two more controls on the front panel, one is an extra (Time/Div Vernier) and the other is a Single Line Scan variable control in the EXT Trigger circuit, and a Norm/Tv push button to opperate in the single line scan trigger circuit.

The back of the Oscilloscope says it has the option 005 fitted, and I have trawled the net and can't find any information on this Oscilloscope, or Option 005 even in the HP Archives.So I am wondering if anyone has this model Oscilloscope and any service/user information?
I have put some pictures to show the difference in the two Oscilloscopes.
The standard HP1742A with option 034 meter.
My HP11742A with option 005.Any help appreciated please.

Thank you,

Gezza123.

[WME_bill]

HP1742A. I have the 1981 cat which describes the 1742A as having time interval measurement. The option 005 (for the 1740A and 1741A) is described as TV Sync. So it looks as though that has been fitted to your 1742A. The manual for the 1740/1741 should be enough for operating and servicing 99% of the machine.
I don't know what you have found from the HP archive site. You may already have seen the 1981 cat. The model is not in the 1975 cat. All analogue scopes have disappeared from the 1989 issue.
I have found the HP archives rather disappointing for such a major manufacturer. Certainly compared with Tektronix. I have manuals for the most of the 180 series + plug-ins and many of the 1700 series, which is more than they have. Sometime, I might scan the manuals and send them over there. But it would be a huge task, as while HP manuals are excellent, the circuits are on very long bits of paper; double A3 usually. Which is almost impossible to scan easily. wme_bill.

[Radio Wrangler]

The 1742 was a bit of a rarity. I've never seen one in the flesh, we used mostly 1740s and the 275NHz variant out of that series.

I think the 1742 versus 1740 difference is in the time interval measurement with the little DMM thingy on the top. Option 5 makes it the TV special with a dedicated line trigger and notice that one channel has AC coupling with DC restoration for TV signals, and that the termination impedance on both channels changes to 75 Ohms.

It was really only of interest to broadcasters/studios/networks, but Tek already owned that market. Not too long after this, Tek brought out their VM700. Even we in the lab HP used one of those for RF video stuff development

The 1740 family are really pleasant scopes, and unlike the Tek 465 don't need a fan whirring away. CRT focus is better, but facilities are less though the differences aren't particularly often used.Blander looking, a bit more reliable, and a hell of a lot cheaper on the second-hand market.

I have two 465s and one 1740.

David

[peter_scott]

BAMA has the 1742A user manual if not the same option.

http://bama.edebris.com/manuals/hp/1742a/

and HP Archive has the 1744 manual

http://www.hparchive.com/Manuals/HP-1744A-Manual.pdf

and the 1740A Service Manual is here:

http://www.ko4bb.com/manuals/index.p...0_Oscilloscope

and here:

http://www.home.agilent.com/agilent/...1&cc=GB&lc=eng

Peter

[gezza123]

Thank you Guy's for your input.
yes I did find that the opt 005 was for the 1740a/1741a but seems to
have been incorperated into the 1742a/005, I have now downloaded the
1978 and 1981 cataloques thanks but still no reference as to it being built in
TV Sync.

I have got a copy of the 1740a service manual and the orignal 1742a user guide, these did come with the scope.

The problem I had was when I got the 1742a someone had brocken the
time/div control in pieces, so had to be repaired.
Also they had twiddled every pot on the A3 vertical preamp board
goodness knows why , as I could only get a display at top of screen in any function or mode.

So I have set it up the best I could with the 1740a manual.The scope is
now very good and all signals seem to be correct an in the 1740a write
up.
I have now downloaded a crap copy of the 1742a service manual, and
noticed the power supply is completely different to the 1740a, the
1742a power supply has got two extra darlington transistors for the
scale illumination/flood gun, and Q5 has been changed to a darlinton there may be other mods on the scope as it was was updated by the manufacturer.
But I still would like to find some more information/pictures on my scope, as was said it may be a special breed .thank you all again Gezza123

[Dekatron]

Here's an Agilent manual that is mentioned as being an "errata" and also named "1742A Oscilloscope Operating and Service Manual": http://cp.literature.agilent.com/lit...1742-90903.pdf - it is complete with schematics and servicing information.

Here you can find the datasheet (product information sheet) on this series of scopes: http://www.k7jrl.com/pub/manuals/hp/...a/174xAtd..pdf

[gezza123]

Hi, Martin thanks for the information, but I have got those.

Also I have spoken to Hp and this is what they say, but they did try and help.
We have checked with our division in the USA and they no longer have any information on the version of the unit that you have.
Apologies for any inconvenience.
Best regards,
****
AGILENT TECHNOLOGIES UK LIMITED

PS:I have now found this article with refference to the Option 005, but this is to be used outside of the instrument, at least it does give me something to go on, I will keep up the search.Thanks again Guy's. Gezza123

[John_BS]

I've got a 1740A with exactly the same option 005 fitted. Similarly, no info on the option!

John

[gezza123]

Hi.John
I am still searching ,took my scope to bits and found that the circuit in the above 900905pdf in post #7, is basically the same one, and all the components shown in the circuit including the two Ic's are in my 1742a.
The only difference is Hp made the circuit board smaller and put three extra controls on the front.
So I am starting to make progress, I would like if possible a front picture of your 1740a/opt 005 or an inside view.Thank you Gezza

[John_BS]

OK: will do when daylight is back!

John

[factory]

Hi Gezza

Yesterday I was sorting though the 50+ manuals I bought from ManualsPlus just before they closed and noticed they have accidentally sent me the 10029A operating note instead of the 11029.

Its the modification procedure & operating note for the TV SYNC add on for the 1715A, 1722B, 1725A, 1727A, 1740A, 1742A, 1743A oscilloscopes, the contents are mostly the same as the PDF in post #7 but with the modification procedure and a cover drilling template. The circuit diagram is A3 and is clearer than the PDF scan, but it doesn't have the component location diagram for the smaller PCB in your scope.

PM me if its of any use to you, as I only collect earlier HP equipment.

David

[gezza123]

HI David,
yes please, I will send you a PM.
I have not found anymore information as yet on my Oscilloscope.
Gezza123