[Pictures] HP 8111A Pulse/Function Generator 20MHz

[Richard W.]

Here are some nice pictures of my new old HP function generator.
Datasheet

As you can see, it doesn't have the burst option, but it's in a perfect condition 

The lids are held in place with a single screw on the backside.
The case looks like plastic, but it's 1mm thick aluminium with a structured plastic coating. Obviously the coating must be cheaper than painting it. Otherwise i don't know the reason for this special construction.

The ICs with the heatsinks are custom ASICS.
The styrofoam-thing on pic 726 / 727 covers some transistors for a current mirror.
On picture 732 / 736 you can see the output amplifier. Note the cooling of the TO-39 transistors. I didn't wanted to remove them.
Picture 740: rainbow-style 

[Richard W.]

more pictures 

[ElektroQuark]

It's like new!
Congratulations for the adquisition!

[david77]

Very nice piece of gear. Congratulations.
I'd suggest replacing that X capacitor on the IEC/input filter. It looks suspiciously like a RIFA brand.
I've had so many of them go up in smoke that I routinely replace them.

[Richard W.]

@david77:
Obviously we had the same thoughts.
Just at the moment you wrote the message, i searched for the list of the dangerous capacitors.
Maybe i replace the whole filter, if its not riveted.

BTW: I can't find that capacitor in the schematic...

[tekfan]

@david77:
Obviously we had the same thoughts.
Just at the moment you wrote the message, i searched for the list of the dangerous capacitors.
Maybe i replace the whole filter, if its not riveted.

BTW: I can't find that capacitor in the schematic...

Yeah, the RIFA caps always go bad sooner or later. Beware of Schaffner mains filters from the 90's which have RIFA caps inside them. I've seen many Solartron 7150 multimeters with blown mains filters. Great little 6.5 count multimeter apart from the filter.

[david77]

That one already looks ready to go bang any time soon 

I wonder why they put it there in the first place. Shouldn't there be one in the filter already?

[saturation]

Yes! Amazing shape.  Have you refurbished, or cleaned it, or have you had it since it was released in the 1980s?

It's like new!
Congratulations for the adquisition!

[Richard W.]

I bought it at a hamfest in Eggenfelden from a austrian seller.
It's maybe cleaned. I've not seen any signs of replaced components or any modifications, the screws aren't scratched.

The scope screenshot shows the fastest possible pulse.
Looks pretty good, even if the measurement was done in MacGyver-style 

I'll try it again with a feed-through terminal, propper cables and a scope which is faster than my TDS2001C

[ElektroQuark]

Yeah, the RIFA caps always go bad sooner or later. Beware of Schaffner mains filters from the 90's which have RIFA caps inside them. I've seen many Solartron 7150 multimeters with blown mains filters. Great little 6.5 count multimeter apart from the filter.

Are those Solartron 7150 easy repairable?
I have seen various rather cheap.

[david77]

Off topic.
Sorry people, switching to German for a moment.

Richard, hast du mehr Info's zu Funk- & Elektronikflohmärkten in Bayern? Findet der Markt in Eggenfelden mehrmals im
Jahr statt oder nur einmal? Ich hab grade schon ein bissel gegoogelt, bin aber nicht richtig fündig geworden.
Eggenfelden wäre zwar ein ganzes Stück zu fahren aber evtl. wäre es das ja Wert.

Gruß, David.

[Richard W.]

@ David77:
There are two bigger hamfests with swapmarkets in bavaria.
One is in Neumarkt/Opf. (always in march/april) and the other one is in Eggenfelden (in october).
Neumarkt is a really big market, Eggenfelden is much smaller.
http://www.afumarkt-nm.de/
Unfortunately the location for the Neumarkt-Swapmarket (the "Jura-Hallen")  are going to be renovated in 2012, so no market in 2012.

In Bayern gibt es zwei größere Amateurfunk-Flohmärkte. Einer ist in Neumarkt/Opf. (immer im März/April), der andere ist in Eggenfelden (im Oktober). Der Neumarkter Flohmarkt ist deutlich Größer.
Nächstes Jahr wird die Halle in der der Flohmarkt stattfindet (die Jura-Hallen) allerdings renoviert, daher fällt der Flohmarkt nächstes Jahr aus.

But now, back to topic 

What should i do with the crappy capacitor? replace or just remove?
I searched around the WWW and most of the HiFi-people which have also problems with these caps just remove them. 

[tekfan]

Yeah, the RIFA caps always go bad sooner or later. Beware of Schaffner mains filters from the 90's which have RIFA caps inside them. I've seen many Solartron 7150 multimeters with blown mains filters. Great little 6.5 count multimeter apart from the filter.

Are those Solartron 7150 easy repairable?
I have seen various rather cheap.

Yes very easy. Just replace the filter and that's it. Maybe you'll also have to clean the board because of the ooze that comes out from the filter. They are made in the early to mid 90's so are relatively new and probably still within calibration. If you can pick one up for cheap go for it. Also you may have to replace the LEDs on the sides of the LCD because those old yellow high brightness LEDs are now just the opposite after almost 20 years.

[ElektroQuark]

Thank you, tekfan.
Those Solartron and Schlumberger equipments always catch my attention.
I like them.

[Richard W.]

Does somebody know which type of hex-key i need to remove the frontpanel knobs?

HP part number: 0370-1005

[tekfan]

Those are 0,05 inch hex nuts.  A 1,3mm should fit those. If you are really desperate to get the knobs off just file a 1,5 hex key down slightly until it fits.

This and a 1/16 inch (1,6mm) is probably all you'll ever need for knob removal from old american test equipment.

[firewalker]

Does somebody know which type of hex-key i need to remove the frontpanel knobs?

HP part number: 0370-1005

You need Allen keys.



Quite cheep set and very useful.

Alexander.

[Richard W.]

@ tekfan: Thank you

(these inch-sizes aren't common here in germany, that's why i had to ask)

[ciccio]

(these inch-sizes aren't common here in germany, that's why i had to ask)

You can find the fraction-inch sized ex-keys on line, here is one example:
http://uk.rs-online.com/web/p/folding-sets/2972660/ (just an example, not sure that this set includes the small-one you are searching for)
Just search for "imperial allen keys".

In one of the first posts, somebody was asking about the  covers, made in aluminum sheet  covered by plastic.
It's a construction method that has some advantages: you buy the already covered sheets, then you cut them, punch them, bend them, and you have the finished cover.
No need to paint it, and to selectively remove the internal paint for reliable contact with the frame. Sometimes it is cheaper...

[rf-loop]

Try find Tektronix oscilloscope what have been in work. These models what have this Tek blue painting over aluminium case. Do you think it is clever?
I have lot of Tektronix painted equipments. All looks less or more bad. I have HP equipments with this plastic over aluminium. They looks like new. Example long time used 1741A oscilloscopes. They have been in heavy professional use and trawel around countri with some service person. Cosmetically they still looks nearly perfect.  Yes I have also Tektronix "travel" scopes. Around scopes this weak painting have scratched and aluminium can see... they looks like garbage collection. (yes some year Tektronix also copycat HP and they use this littlebit HP like plastic over aluminium (but maybe only in more expensive units?), these models looks still lot of better than painted.)

[Richard W.]

I ordered the .05inch hex key at a local tool-shop. The price is 22ct + VAT

[...] In one of the first posts, somebody was asking about the  covers, made in aluminum sheet  covered by plastic.
It's a construction method that has some advantages: you buy the already covered sheets, then you cut them, punch them, bend them, and you have the finished cover.
No need to paint it, and to selectively remove the internal paint for reliable contact with the frame. Sometimes it is cheaper...  [...]

[...] I have HP equipments with this plastic over aluminium. They looks like new. [...]

That's true 

[wacatt]

Hi Richard

I have recently acquired exactly the same model. I find it a bit strange when I was playing around with it. On my machine, the "compl" button does not engage as  other buttons on the same row do which are merely basic on/off switches. Instead, it feels like a spring loaded trigger action. 

Since I don't have a spare one to compare nor it mentioned on the service manual, can you tell me how does the "compl" button suppose to function?