Lowry Organo -for parts?

[Firestorm]

Check this out. The specific part isn't listed, but you get an idea of what these were about.
http://www.nostalgickitscentral.com/inf ... labpec.pdf

[Phil_S]

Wow':o'
Where do you come up with this stuff?
I still have zero comprehension about what this thing did in the organ. There are 4 of them in each of the twelve tone generators on the 12AU7's.

[selloutrr]

tone generator - they were probably used to set the frequency sweep that was generated.

[Firestorm]

These things are actually pretty cool in a history of electronics sort of way. They were called PECs, for Printed Electronic Circuit (or sometimes Packaged Electronic Component). Centralab's brand name for them was Couplate. Old-time radio and TV repairmen called them "centipedes." In some sense they are the ancestors of integrated circuits, though everything inside these is strictly passive.

They came about during WWII when Centralab developed a process for mass-producing proximity fuses that could withstand being fired from an anti-aircraft gun. Using a ceramic base, they printed metallic paint for connectors, carbon paint for resistors and added conventional ceramic caps as needed. By the 1950s, they were used in virtually every tube television set manufactured. Since you could have CRL customize any reasonable combination of resistors and caps (a few had diodes, too), you also find them in Ampegs like the B15, in many Dynacos and apparently in Lowrey organs.

It's amazing what you can discover on the Webbernet...

[lzzrdgrrl]

Each of the twelve little boards has 3 Tropicaps, 1 BB, 8 or 9 red Erie disk caps, ~ 3 dozen carbon comp resistors, possibly something else. I am guessing, if I made this a "vacation project" it would take me a whole week to extract all the parts and sort them. What surprises me most, though is how many of the parts are commonly used in guitar amps. I was half expecting a pile of stuff that generally isn't used. There are also several thingies (technical term) that are about 1" square and have a number of leads. When I have one free, I'll post a picture -- maybe someone knows what it is.

I dived the carcass of an Organo Model 06 out of the bin and all the good parts have been taken. Valves, transformers, wire harnesses.... everything. I have the octave and-a-half keyboard and the twelve tone boards such as they are, and I fancy making those work again for some obscure purpose, but the component that's somewhat interesting are the RF tuning coils with the immense one-inch windings. The oscillator for the low end of the octave? If nothing else, I have some oil-filled caps, some micanol octal sockets and about four dollars of scrap metal with is what I thought I got in the first place..... XDDD......

[Phil_S]

I've begun to harvest the parts off the tone modules. It is very slow work. Parts are wrapped around terminals, sometimes with two loops and I'd like to preserve lead length if I can. Let's say, there are days (evenings, actual) when I just want to be at the bench with a hot soldering iron in my hand and it lets me unwind a little. It will probably take me months to harvest all the caps and resistors. There are lots of 100K and 470K carbon comps. I'm thinking I'll end up with well over 50 of each. I'm working hard to recover the bumble bee cap from each of the 12 modules, as these seem to fetch good prices on eBait.

Is there any way for an amateur with limited equipment to more efficiently desolder the boards? The assembler, in some places, applied solder liberally.

[selloutrr]

solder wick and a solder sucker.

You might have luck with needle nose plyers,
apply heat until the solder pools,
pull the lead get off the solder let it cool,
move on to the next,
do several come back to the first after it's cold and repeat until it's free.
The trick it to not over heat the part.

it's probably not worth the investment but if you did this on a regular basis a desolder / rework station would turn your hours into minutes.

[lzzrdgrrl]

· Hold assembly in one hand and iron in the other

· Apply heat to the join until the solder pools

· Give the assembly or part a sharp snap, the action is all in the wrist

· Hope the solder splash comes off the panelling

XDDDDD..........

I have been told that there are good bumblebees and there are bad ones. The ones to avoid are the paper caps and they are all junk. Those are identified by a solder blob-like bead on the foil side lead right next to the body, which is often burned so you can't read the bands.......

I also sourced some IRC carbon resistors between one and five watts, NOS in many cases, but always discarded because they are 'noisy'. Same with all the oil-filled coupling caps. 'Centipedes' and other TV parts like trimpots, caps and components identified only by stock number invariably get binned. I have more than enough for my needs - I just hate seeing this stuff go to waste.....

[Cliff Schecht]

Yeah one of my favorite tricks to teach during my bi-annual soldering tutorial is how to quickly heat up a solder joint and give it a decent SMACK on the work bench. With practice it'll knock the solder clean off without making a mess. The trick is obviously to smack the board down in such a way that the solder goes away from the components you want..

[Cliff Schecht]

Also, have you considered hot air? Is it possible to use quickly?

[Phil_S]

I've been using the solder sucker, and the smack technique. Maybe I'll try the soldering iron and a vacuum hose. That's a beeping noisy way to go though. This old solder tends to liquify quickly and then solidify quickly. I don't think braid will do much given the amount of solder.

I understand this could be a fools errand. It is just something to pass a bit of time when I need to get away from whatever.

Thanks for the suggestions.

[lzzrdgrrl]

Having dropped the stop panel and shattered the keys, I decided to part out the carcass. There's bumblebee caps galore, but they are all the PAPER ones. I suppose they are oil-filled, too, but these are the sort that are notoriously bad. Experienced hi-fi amp guys just cut these out and bin the lot. I'm talking about the bumblebee that has the solder-blob off the foil end of the body. Later versions don't have the blob but have the bands stacked towards the positive end so you can tell polarity that way. These, I've been lead to believe, are the ones you want to use.......

All I know is this variety of cap is either shorted or about to go short. You can really use these?.......

[Phil_S]

These have the blob of solder? I take it they aren't the desirable ones?

[lzzrdgrrl]

Lookin' at mine, they look the same. The added 'bump' is a feature I don't have. It would be a shame if you can't use 'em, but I don't know. Hi-fi phreaks are noise-o-phobics more so than connoisseurs of sound, and OCD about specs besides.....

We need to hear from a bumblebee expert. What's the verdict?.......

[Structo]

Man, those old tone generators were a real work of art.

I think if I had that I would just hang it on a wall to look at.

Can you imagine building one of those?
Probably take a week of soldering if not longer.