Author Topic: Standard procedure for repair?  (Read 694 times)

0 Members and 1 Guest are viewing this topic.

Offline bfh47

  • Contributor
  • Posts: 5
  • Country: gb
Standard procedure for repair?
« on: June 07, 2020, 08:32:04 pm »
Hi,

This appears to be an open-minded forum for newbie questions, I only hope that threads are not lost in a rapid torrent here!

I don't even own a soldering iron at this point, (getting one shortly) I have to do work on an organ from 1970:

When desoldering and working on boards. I understand it's best to be on a heat proof mat, at a desk, with good lighting and some sort of fan to blow smoke away.

Here's the thing, this organ has many different sections items (quadrant sliders, knobs, switches, tone generator boards, the key section), and everything is wired together with soldered wires, it's not possible for me to remove any component out of it's wooden case to even start working on it.

I would have thought that you're not supposed to do any soldering actually inside a unit? But this appears to be a paradox as you'd have to desolder a component at every single connection that holds it, just to take it out to do work on it. And I know this might sound super specific, but I think the general idea behind it is not. I took apart my stereo receiver a while back (a different decade entirely) and there were many things attached to each other in ways seemingly inseparable without a soldering iron (back then I was only equipped with a compressed air can anyway). So I think it's potentially not a bad question to ask.

I can provide pictures if anybody wants to give *specific advice* or if it's not clear.

 

Online Mr. Scram

  • Super Contributor
  • ***
  • Posts: 9504
  • Country: 00
  • Display aficionado
Re: Standard procedure for repair?
« Reply #1 on: June 07, 2020, 08:57:55 pm »
Hi,

This appears to be an open-minded forum for newbie questions, I only hope that threads are not lost in a rapid torrent here!

I don't even own a soldering iron at this point, (getting one shortly) I have to do work on an organ from 1970:

When desoldering and working on boards. I understand it's best to be on a heat proof mat, at a desk, with good lighting and some sort of fan to blow smoke away.

Here's the thing, this organ has many different sections items (quadrant sliders, knobs, switches, tone generator boards, the key section), and everything is wired together with soldered wires, it's not possible for me to remove any component out of it's wooden case to even start working on it.

I would have thought that you're not supposed to do any soldering actually inside a unit? But this appears to be a paradox as you'd have to desolder a component at every single connection that holds it, just to take it out to do work on it. And I know this might sound super specific, but I think the general idea behind it is not. I took apart my stereo receiver a while back (a different decade entirely) and there were many things attached to each other in ways seemingly inseparable without a soldering iron (back then I was only equipped with a compressed air can anyway). So I think it's potentially not a bad question to ask.

I can provide pictures if anybody wants to give *specific advice* or if it's not clear.
I don't see why you wouldn't solder inside a unit. It may not be very convenient and doesn't really work well with modern production line methods, but you can. I suspect the organ is built by hand and possibly in small volumes, so that doesn't really apply.
 

Online bdunham7

  • Frequent Contributor
  • **
  • Posts: 825
  • Country: us
Re: Standard procedure for repair?
« Reply #2 on: June 07, 2020, 09:00:25 pm »
Post pics.  You should take a lot of pictures before you start and as you are working so that you don't forget how it goes together.  What sort of organ?  Is this one that has the rotating tone wheels?
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit DMM is good enough for most people.
 

Offline bfh47

  • Contributor
  • Posts: 5
  • Country: gb
Re: Standard procedure for repair?
« Reply #3 on: June 07, 2020, 09:41:16 pm »
To m3vuv: A little difficult to refer to common sense when everything I encounter/learn about, is for the first time!

Regarding the organ, definitely not one anyone here has seen or worked on (bold assumption, i'm aware. The schematics for it, I have, but I also know they have not been scanned anywhere on the internet. Just a standard transistor organ a few years before they switched to silicon components instead of germanium transistors. Sorry

I am starting to restore it, not with circuitry repair, but with cleaning the key contacts. Anyway, there are some bars used to hold the contacts, they are soldered at the end as shown by these pictures here (https://imgur.com/a/cUEhKlM). There is only one component soldered here, and so once I have some experience, this would be a fairly "safe" procedure I think.

The goal would be to de-solder that fat blob, so that I can pull out those 5 rods soldered there. Get better access to the contacts, and give them a proper cleaning.

Do i need to have a solder-sucker tool at the ready, and just go at it with a solder iron to melt it? There are no components underneath but just the "bed" of the inside, should I put something underneath in case some molten solder falls down? Should I buy another heatproof mat and cut a small area, put that piece under what i'm working on?

No doubt some of these questions will seem stupid to me in the future. But as it stands, I really am this clueless.
« Last Edit: June 07, 2020, 09:46:53 pm by bfh47 »
 

Offline tpowell1830

  • Frequent Contributor
  • **
  • Posts: 772
  • Country: us
Re: Standard procedure for repair?
« Reply #4 on: June 07, 2020, 09:54:56 pm »
To m3vuv: A little difficult to refer to common sense when everything I encounter/learn about, is for the first time!

Regarding the organ, definitely not one anyone here has seen or worked on (bold assumption, i'm aware. The schematics for it, I have, but I also know they have not been scanned anywhere on the internet. Just a standard transistor organ a few years before they switched to silicon components instead of germanium transistors. Sorry

I am starting to restore it, not with circuitry repair, but with cleaning the key contacts. Anyway, there are some bars used to hold the contacts, they are soldered at the end as shown by these pictures here (https://imgur.com/a/cUEhKlM). There is only one component soldered here, and so once I have some experience, this would be a fairly "safe" procedure I think.

The goal would be to de-solder that fat blob, so that I can pull out those 5 rods soldered there. Get better access to the contacts, and give them a proper cleaning.

Do i need to have a solder-sucker tool at the ready, and just go at it with a solder iron to melt it? There are no components underneath but just the "bed" of the inside, should I put something underneath in case some molten solder falls down? Should I buy another heatproof mat and cut a small area, put that piece under what i'm working on?

No doubt some of these questions will seem stupid to me in the future. But as it stands, I really am this clueless.

Your intuition is good, use it. Not many here have done what you are proposing, so your results will vary, depending on your decisions going forward. So far, nothing that you have proposed seems terribly out of the sphere of possibilities.

I hardly would be concerned about fire... but, if you heat the wood too much, you could damage it, so be cautious.

I wish you good luck and good repair...

EDIT: Show us the finished product when you succceed.
« Last Edit: June 07, 2020, 09:58:09 pm by tpowell1830 »
PEACE===>T
 

Online Mr. Scram

  • Super Contributor
  • ***
  • Posts: 9504
  • Country: 00
  • Display aficionado
Re: Standard procedure for repair?
« Reply #5 on: June 07, 2020, 09:58:59 pm »
I don't think you necessarily need a heat proof mat to catch any solder. Things like paper or a piece of cloth will probably do the job. Just remember the solder is likely to be leaded, so be sure to dispose of it and anything it falls on properly to avoid contaminating the world even further.
 

Offline james_s

  • Super Contributor
  • ***
  • Posts: 12245
  • Country: us
Re: Standard procedure for repair?
« Reply #6 on: June 07, 2020, 10:08:25 pm »
As with most things, it depends. If you have extensive repair work to do it's often easier to remove the PCB or subsection that you're working on and work on the bench. Other times it makes more sense to do the work in place. You have to weigh the effort of removing and installing the board vs the greater convenience of working on a bench.

What specifically is wrong with the organ? The first step is to assess the problem and make sure you understand enough about how it works to effectively diagnose the problem and repair it rather than mangling the thing and turning what started out as a simple repair for a competent tech into a complete write-off, seen it many times.

If you have never soldered before I would recommend finding some other junk to practice on before you tear into that. It's usually not too difficult to acquire a bunch of broken stuff, an ad on craigslist or a visit to an ewaste recycling event can net you all the stuff you can carry.
 

Offline bfh47

  • Contributor
  • Posts: 5
  • Country: gb
Re: Standard procedure for repair?
« Reply #7 on: June 07, 2020, 11:11:04 pm »
Thank you to all the replies. There are a number of issues with the organ which I hope to fix one by one. I have to say: everything functions, every single key, every single tone generator, every single effect, just some things function less well than others. Those issues I will be working on in the future. And also, despite using germanium transistors, research tells me that many common soviet components are used here, should I need to source anything, I am not worried, as I even speak russian).

But the biggest multifaceted issue is to do with the "action" of the keys. The 5 contacts associated with every note are not activated simultaneously as the key is pressed down, but rather one by one, I think this is because the contact surface is not clean. I can confirm this visibly (as in, I can see what a clean section of contact looks like, and what a dirty section looks like).

the contacts are held in place by precise pieces of plastic, so contacts being "bent" or anything like that is no excuse. And due to the fact this issue occurs with all keys to a varying extent, I think this is just due to built up gunk from years of having "contact cleaner"-type stuff sprayed on the contacts. My thesis is that a slightly "better" than typical connection needs to be made now, before the electrical contact happens, as in the contacts need to be pressed up against the rod slightly harder, with slightly more surface area, that pressure is granted as the key is pressed deeper, resulting in staggered activation. Just a thesis.

Yeah, a pretty niche issue, with what hopefully will be a pretty niche solution.

I am going through the original service manual quite slowly (it's in german, I do not speak german), it even has a section on "common troubleshooting", maybe I will find something. It is a few weeks still before I get a soldering iron. So by that time I hope to be otherwise prepared.

See those 5 thicker rods in the keybed in th 1st picture from my previous post? Those are the rods the contacts touch when a key is pressed. I have no idea what the other 5 rods skinnier rods are for, but I can tell you now they are far less electrically involved, to my knowledge they serve the purpose of helping hold the 5 octaves together in a line (each octave has it's own circuit board). Following the wires, I believe they just ground to a metal component inside the organ. After a small amount of soldering, they should just slide out (they're almost a metre in length each, i'd say).

They are what is stopping me from getting a q-tip soaked in isopropyl between each contact and it's associated "big" rod. So yeah, all this work just to clean some contacts.

And after that point, i'll already have all the means (not necessarily the knowledge!) to work on the tone generators and whatever else.

I have soldered before (in a fun, let's-see-how-this-works, not-gonna-care-about-the-outcome scenario, supervised by a professional), and the circuitry inside this organ does "appear" less complicated in some ways (back then I remember trying to solder a chip with about 12 legs on each side, modern component, all the legs closely together, yikes, whereas here there are resistors, transistors, and things are spaced out quite nicely). I plan to practice for at least 2-4 months before seriously doing anything to the organ, practicing: soldering, de-soldering, working accurately, using a solder-sucker, operating quickly, working out some solution for ventilation (i'm only going to ever realistically use leaded solder). Not quite on scrap-electronics, but with things that can at least give me a response or indication as to whether the electrical connections I made were successful. I think there exist kits specifically for this educational purpose, I will likely start there.

Here's a zoomed out picture of the keybed, (
) with all keys removed. You can see I have made a start on taking out plastic components from the left hand side as part of the process of getting better access to the contacts. Ignore the annotations.

I have to restrain myself quite strictly as I'd love to ask more (related) questions but I am aware it is the rule of forums not to go off on tangeants.

Thanks to everyone for the replies. I will take my own advice (ha!) and make sure I am careful when working on things *inside* the organ. But before i got the answers I did here, I didn't even know that was allowed!
 

Offline tkamiya

  • Super Contributor
  • ***
  • Posts: 1438
  • Country: us
Re: Standard procedure for repair?
« Reply #8 on: June 10, 2020, 01:21:27 am »
This forum is pretty good about newbies.  Don't be afraid!

As to repair, there is no rule, except to do what it must be done.  If you must solder inside, do so.  If you can take the part out easily, do so. 

But I do advice, practice soldering and de-soldering on something else.  It isn't something words and pictures can explain.  You'll have to develop a feel for it.  Then you won't need heat protection pad unless it's a really tricky location. 

First thing I'd do when I repair something is visual and smell test.  I spend good day or two visually inspecting every part, every joint, and every wire.  Sometimes you can find a fault by smelling a faint smell of burning.  Something like chopsticks will become one of your valuable tools.  If something is making intermittent connection, slight pressure will show it. 

Good luck. 
 

Offline Gyro

  • Super Contributor
  • ***
  • Posts: 5705
  • Country: gb
Re: Standard procedure for repair?
« Reply #9 on: June 10, 2020, 11:36:43 am »
To m3vuv: A little difficult to refer to common sense when everything I encounter/learn about, is for the first time!

It would be as well to start quoting m3vuv's posts in replies. He has developed a nasty habit of making snide comments and then deleting them.
« Last Edit: June 10, 2020, 12:10:07 pm by Gyro »
Chris

"Victor Meldrew, the Crimson Avenger!"
 

Online tggzzz

  • Super Contributor
  • ***
  • Posts: 12106
  • Country: gb
    • Having fun doing more, with less
Re: Standard procedure for repair?
« Reply #10 on: June 10, 2020, 01:02:48 pm »
Pace Basic Soldering Lessons 1-9 show good examples of what you should see happening when you've got it right - and just as importantly - wrong. The only omission is SMD components, presumably they weren't common when the videos were made. But try not to snigger at the pronunciation of “solder”!

You will probably realise that you should practice before attacking something that matters.

Take lots of (in focus!) digital photos, before you start, so that you can see what goes back where.
Make crude drawings of what screwa/cables you remove, so that you can see what you have to put back and where.
Keep removed screws etc in small plastic bags or drawers. If there are multiple stages of disassembly, keep each stage separate from the others.

For cleaning contacts there are two basic techniques.

For anything with gold fingers, dip a piece of smooth paper in IPA (isopropyl alcohol), and slide it between the contacts in such a way that it does not catch and bend the fingers.

Use a commercial cleaning compound, e.g. one of the Caig DeOxits. There are many varieties, with major divisions:
  • for gold contacts
  • for carbon contacts inside pots
  • for other contacts
  • concentrated so you only need a tiny amount, possibly applied as a drip on the end of a screwdriver
  • less concentrated, so you can spray it and let the volatile compounds evaporate
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline DaJMasta

  • Super Contributor
  • ***
  • Posts: 1920
  • Country: us
    • medpants.com
Re: Standard procedure for repair?
« Reply #11 on: June 10, 2020, 05:56:30 pm »
An organ repair is going to be a lot more mechanical than electrical, I think, and while you may certainly have to solder-in-place, keep in mind that the people installing it would have had to as well, so maybe there's a way to remove a terminal block, or remove a part blocking a board's removal, or something similar that would actually give you far better access.  Organs are also meant to be maintained in the long term, so I would not be surprised if there were ways to get at hard-to-access parts easily with a release of a mechanism or screw.  That said, since they've almost undoubtedly been worked on before, there could be some hackjob/patch of a repair that makes it again more difficult.  Do what you can to make it easier to access for the next tech to work on it!

If you're not loading too much solder on the tip and aren't moving the iron too quickly, you shouldn't be splattering much solder around, so it's not entirely required to have something to catch it (it's also low total mass, so even if it lands on something flammable, the heat sharing to heat up the thing it lands on will probably cool it so much it's unlikely to actually light).  Blowing away the fumes is preferable, but as long as you can avoid breathing the fumes (flux burning off) you should be fine.

It's going to be leaded solder (and leaded pipes, usually!), so just make sure to wash your hands before eating or touching your face afterwards.  Especially for larger/older/grimier contacts, having some extra flux to clean can be very useful (not the kind for plumbing, a kind for electronics and preferably a no-clean formula), and having some isopropyl alcohol to clean off flux residue or other grime can be good too.

There are tons of soldering tutorials around, as well as discussions of ways to join wires, or what alloys/fluxes to use, or whatever, the internet is a great place for it, but it's always good to find multiple sources or something from a major "authority", at least.

It does sound to me like a lot of your work will be contact cleaning and/or mechanism adjustment to get the contacts to be actuated properly, but that means a lot won't depend on your soldering skills (and with the size of the contacts you'll be working with, it's much more forgiving than modern fine pitch electronics!)
 

Offline bfh47

  • Contributor
  • Posts: 5
  • Country: gb
Re: Standard procedure for repair?
« Reply #12 on: June 11, 2020, 06:25:30 pm »
Thanks to everyone for the replies and the positive feedback. Currently stuck on another piece of the puzzle, replacing highly specified injection moulded components which broke in the keybed.

I am still looking at options for cleaning the contacts without removing those metal rods. The soldering station I was going to get is apparently out of stock till 2 months time, giving me a chance to reconsider some ideas and develop some new ones.
 

Offline DaJMasta

  • Super Contributor
  • ***
  • Posts: 1920
  • Country: us
    • medpants.com
Re: Standard procedure for repair?
« Reply #13 on: June 11, 2020, 08:23:31 pm »
Another thing that is often out of stock in our current world situation.... but have you looked into 3d printing the parts?  For low volume parts, it can do a very good job, and given the nature of organs, they probably qualify.  There are some geometries and surfaces that are very difficult to make, but a lot of pieces can be replicated in CAD software and then printed and tweaked as needed.  Takes some specific expertise, but there is even some access to printers in public spaces, so it could be a viable option.


It's also possible to make standard silicone molds and copy parts in resin, but it's probably going to take more time to setup (provided you have a working printer already) and it's going to take comparatively more effort per copy of the part, whereas with a printer you just need the time and the filament once your design/print settings are good.
 

Offline bfh47

  • Contributor
  • Posts: 5
  • Country: gb
Re: Standard procedure for repair?
« Reply #14 on: June 13, 2020, 08:39:19 pm »
DaJmaster i'm already one step ahead of you. Some components are broken (i haven't mentioned it, it's to do with a different issue), and yes, I am looking at getting these 3D printed using polycarbonate. I am not doing it myself though, and so the cost will be quite crazy for about 10 of them. At least I will maintain my moral compass, as the alternative is buying a similar organ from the same company (also from the 70s) and stealing the components from it.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf