From an old post:"Binding post to BNC adapters. I have some Pomona adapters. I agree they are decent for the money. What I can't find are the dual binding post plugs with the ground skirt. Maybe they will be a DIY thing."
General Radio 274-QBJ or POMONA 1645 are life savers, worth there weight in GOLD.
Duke🙂
General Radio 274-QBJ or POMONA 1645 are life savers, worth there weight in GOLD.
Duke🙂
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My HP 3580 has 'those knobs'. Every time I turn a knob, I'm as gentle as can be. I know the HP scopes of that generation use the same type of knobs. May want to search eBay for a parts unit.
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Sent from my SM-J320V using Tapatalk
Hi KC,
I had already decided I would have to make my own ugly ones, but I misplaced my banana "pins". I'll use plastic sheet and some copper sheet. They will be crude, but I can't afford a bunch of those.
Hi Dave,
I found that "Gorilla Glue" works very well on those HP knobs. My 339A is pieced together with the stuff, and I have an older 3580 (mechanical crank knob) that has disintegrated. If I can find all the pieces, the glue might save it. It's really too bad that plastic doesn't seem to last. Tek 'scopes have the same damn problem too. Especially the 2235 and similar models.
-Chris
My, they are dear, aren't they!
I had already decided I would have to make my own ugly ones, but I misplaced my banana "pins". I'll use plastic sheet and some copper sheet. They will be crude, but I can't afford a bunch of those.
Hi Dave,
I found that "Gorilla Glue" works very well on those HP knobs. My 339A is pieced together with the stuff, and I have an older 3580 (mechanical crank knob) that has disintegrated. If I can find all the pieces, the glue might save it. It's really too bad that plastic doesn't seem to last. Tek 'scopes have the same damn problem too. Especially the 2235 and similar models.
-Chris
I can vouch for that stuff.
While I was cleaning the switch wafers last week and rotating them back and forth one of the knob's tab or wing, or whatever you want to call it fell off in my hand. I ran up to the big hardware store and picked up some Gorilla glue. I got a bit sloppy with the glue and its not pretty but at least I have the tab back on the knob and its seems fairly solid.
They come in very handy when you have the gain cranked to 80dB or more on an analyzer..
Hi David,
That is absolutely true. I guess I should get one at the very least. I was hoping to save the $$. Darn. Since you put it that way, I really don't have a choice - do I?
-Chris
That is absolutely true. I guess I should get one at the very least. I was hoping to save the $$. Darn. Since you put it that way, I really don't have a choice - do I?
-Chris
Hi David,
I just ordered my adapter. Their shipping to Canada is ghastly! $44 and change USD !!
-Chris
I just ordered my adapter. Their shipping to Canada is ghastly! $44 and change USD !!
-Chris
Ouch! I collected them from local surplus stores and eBay over the years. Why isn't China watching? These would be less than $2 OEM in any quantity if someone was making them. They may not be of the GR quality and fit but probably more than good enough.
I do understand why they may not be common any more. With the need for shrouded banana connections and flush female connection in panels they don't work on new stuff.
Dealing with the variety of audio interfaces and levels is quite the headache. I must have about 10 Lbs of adapters from N to UHF to BNC to 1/4" to XLR to RCA to 3.5 MM to 2.5 MM. Not to mention microdot, SMA SMC and GR874. And then add in balanced vs. unbalanced. Too much.
I do understand why they may not be common any more. With the need for shrouded banana connections and flush female connection in panels they don't work on new stuff.
Dealing with the variety of audio interfaces and levels is quite the headache. I must have about 10 Lbs of adapters from N to UHF to BNC to 1/4" to XLR to RCA to 3.5 MM to 2.5 MM. Not to mention microdot, SMA SMC and GR874. And then add in balanced vs. unbalanced. Too much.
Hi Demian,
Expensive yes, but I had to address my very real problems, and I am stuck with those older instruments for a while yet. I converted a couple cheaper devices to BNC, but I don't want to chop up an HP 339A, or my old 3581B or 3580A. So these will be used with those older pieces of equipment. I even have a 654A and 334A to use these with ('cause I like those instruments, I remember using them for work).
Anyway, it's done and ordered. Some day it will show up and I have one more issue dealt with. As for adapters, yes. You need a lot of them. I don't have enough, but they still overflow a little drawer (from a parts cabinet). They are split up between types (RF, audio and LF stuff).
-Chris
Expensive yes, but I had to address my very real problems, and I am stuck with those older instruments for a while yet. I converted a couple cheaper devices to BNC, but I don't want to chop up an HP 339A, or my old 3581B or 3580A. So these will be used with those older pieces of equipment. I even have a 654A and 334A to use these with ('cause I like those instruments, I remember using them for work).
Anyway, it's done and ordered. Some day it will show up and I have one more issue dealt with. As for adapters, yes. You need a lot of them. I don't have enough, but they still overflow a little drawer (from a parts cabinet). They are split up between types (RF, audio and LF stuff).
-Chris
I remember seeing a prototype 339A that had knobs with 'flat' (non-engraved) skirts. The markings were on white label tape applied to the skirts. Not pretty, but workable. One could probably 3D print something these days.
Hi Brian,
You know what? There is a market for this. I have a 339A that needs almost all the knobs. Similar instruments, like the 239 oscillator, 3580A, 3581B/C and I'm sure there are several others that need attention.
-Chris
You know what? There is a market for this. I have a 339A that needs almost all the knobs. Similar instruments, like the 239 oscillator, 3580A, 3581B/C and I'm sure there are several others that need attention.
-Chris
These guys make knobs with clear skirts https://www.selcoproducts.com/knobs You could make a set of transfers with the correct graphics for them. The collet knobs they make are quite good. The minimum order is 50 but they would be in the $3-5 range and a group buy for full sets for various HP products would probably blow through 50 quite quickly. Make up sheets with the transfer graphics for the clear skirts and its a sort of DIY HP restoration project. There are a lot of devices here with similar knobs: Signal Generator The HP8640 has a huge following as well.
> knobs with clear skirts
Not so unusual ?
http://www.rogancorp.com/knobs-hand...ar-plastic-skirt-aluminum-skirt-control-knobs
IBK-1005-2 light gray, clear skirt | Skirted Bar Knobs | Buckeye Shapeform
3A/5A Style Small Skirted Knob
Patrick
Not so unusual ?
http://www.rogancorp.com/knobs-hand...ar-plastic-skirt-aluminum-skirt-control-knobs
IBK-1005-2 light gray, clear skirt | Skirted Bar Knobs | Buckeye Shapeform
3A/5A Style Small Skirted Knob
Patrick
I always thought the Buckeye knobs were a little horsey, but the real value of the selco knobs is the collet fastening. There are probably others as well.
After looking at the 339 for a bit it seems to me that it might be best to take the 5 upper knobs off and have a rectangular overlay made that covers the whole upper section. Make the overlay out of anodized aluminum and have the numbering laser etched into it. If you extended the plate size out you could have the new lettering cover the old lettering on the 339A faceplate as well, i.e. "Distortion Range", "Input Range", etc and have holes put in it for the input range LED's. It could be made out of the same gauge material as the washers behind the shaft nuts so the shaft nuts would hold the plate down. Then you could use whatever pointer knob you liked as long as it fit inside of the permanent graphics.
I also thought about making a vinyl overlay in the same shape, but it would be a lot more durable in anodized aluminum.
I know you'd still have the oscillator level knob to deal with. You could extend the plate down to overlay the osc. level knob as well, but that would probably increase the cost of the plate somewhat due to the odd shape. It seems to me like the upper row is typically in the worst shape.
I also thought about making a vinyl overlay in the same shape, but it would be a lot more durable in anodized aluminum.
I know you'd still have the oscillator level knob to deal with. You could extend the plate down to overlay the osc. level knob as well, but that would probably increase the cost of the plate somewhat due to the odd shape. It seems to me like the upper row is typically in the worst shape.
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Those are all good suggestions. Maybe a thread for designing these knobs and determining what design and who we go with? It might not come to anything, but let's give it a poke to see what happens. I also like the idea of a new face plate section, and you're right KC, the upper section is where most of the problems occur.
Hi Demian, yes. I also have an 8640B. Those knobs are okay so far, but there is a broken gear on the range switch. I have a spare, so some day I'll take it apart and fix it.
-Chris
Hi Demian, yes. I also have an 8640B. Those knobs are okay so far, but there is a broken gear on the range switch. I have a spare, so some day I'll take it apart and fix it.
-Chris