Replacement switches for Harrison console

Hi,

The original ITT switches of our Harrison TV-3 console are getting bad.. the mechanics are getting broken and contacts are oxidated. I tried to google for replacement but couldn't find ones which would fit the holes of the originals (as you can see in a picture, the legs are not evenly spaced).



Do you have an idea where you could find this kind of ones (most of the switches are 6pdt)? Or any alternative solutions?

Thanks,
- Lauri / Astral Studio

http://www.groupdiy.com/index.php?topic=36655.0

..they are probably the infameous ITT dialastat-type switches?

If so, sometimes available in well-assorted SSL, Neve, or Calrec repair shops. Not cheap.

Sometimes you can fix them by inserting a new locking pin (from a similar switch) and cleaning.

Jakob E.

Hey,

I might have some spare ones pm me! I'm currently refurbish my H-TV3!

//Robert

gyraf said:

http://www.groupdiy.com/index.php?topic=36655.0

..they are probably the infameous ITT dialastat-type switches?

If so, sometimes available in well-assorted SSL, Neve, or Calrec repair shops. Not cheap.

Sometimes you can fix them by inserting a new locking pin (from a similar switch) and cleaning.

Jakob E.

Click to expand...

Hi,
they seem to be the same switches. Thanks for the information.
We have cleaned them with KF K2 spray without opening the switches, and it works for a while but is not very reliable solution.

-Lauri

Try these folks.
http://www.citrelay.com/
Bruno2000

gyraf said:

http://www.groupdiy.com/index.php?topic=36655.0

..they are probably the infameous ITT dialastat-type switches?

If so, sometimes available in well-assorted SSL, Neve, or Calrec repair shops. Not cheap.

Sometimes you can fix them by inserting a new locking pin (from a similar switch) and cleaning.

Click to expand...

Thank you for the tip! We managed to fix the latching of every switch by replacing locking pins from unneeded automation swithces! 8)

But the contact problem still exists: KF K2 spray or Caig DeoxIT cleaning thing work both pretty well for a while, but are not very reliable..
So we started to think about an ultimate solution: to replace swithces with relays. I do not have much experience of electronics so have no idea is it possible to find cheap enough relays with suitable pinouts, and how to fit both a relay and a controlling switch to the pcb... What do you more experienced people think, would it be impossible, a nightmare to do or something to consider?

I've owned my Harrison MR-4 since 1981 (bought New) .
I was told early on to never clean the switches and I haven't and all are working good except for a few.
I called Harrison years ago and was told the switches are no longer available they are not  being made anymore.  I've since bought 2 other Mr-4 for parts.
I had my master modules and one input module redone by Jim Williams of Audio Upgrades.
He replaced all caps using Panasonic FM's, Wima's, multicaps, ceramics, elimimated unneccesary caps,
and replaced all the IC's. He also built 4 Class A amps for the 2 programs outs, replacing the 5534's.
Redid the mic pres, line drivers and vca cards. It sounds great.  I'm in the process of redoing all the input modules.
My idea for the few bad switches is to take them apart and reapply the orginal vaseline type substance.
I haven't done this yet and don't know what the substance is. If i do I'll let you know.

So they recommended not using deoxit on the switches? Does it eat up the plastic? The switches on my tv4 are all still working. Maybe because mine is a newer early 90's one? I'm curious about all of your mods/ recapping upgrades. Also winetree or anyone else have any extra switch caps or meter card motherboards?

Give Electrolube EML a try.

http://www.electrolube.com/docs/lubricant.asp

And if that doesn't work you can try these guys

http://www.stanler.co.uk/switches/switchframe.html

Mark

Duantro,
Yes, the cleaners eat the plastic. The switches are pre lubed and good for a million pushes.
Like I said I have 2 other consoles for parts over 50 complete extra modules.
Yes I have caps in all the colors. I'm not sure I understand meter board motherbords. My consoles have edge card connectors wired together for the 32 segment meters.
Mods, there are many. I'd be willing to talk to you as I talk faster than I type.

I've dealt with more dialstat switches than I'd care to recount. They are also used in the buss section of SSL4000 series and the Neve 51 and V series.
Deoxit is not good for them it drys out the mechanism and often will lead to the latching pin breaking.

Stanler is the only source of these switches and they are expensive.

Here's some tips:
EML200F is the best cleaner as it also lubricates.
The best way to clean them is in an ultrasonic bath with a water / ammonia mix. However this will also clear out the white grease around the latching pin. So, I clean them in a ultrasonic bath, wash with clean water, blast out with an aircompressor, give a tiny squirt of EML or pro gold, THEN, replace the latching pin with a new one and add some white grease around the pin. It is time consuming and depending on how you value your labour, arguable just as expensive as buying a new one.
When replacing a broken latching pin be sure to look in the mechanism under a magnifying glass to ensure you get out any little broken
bits of the pin, needle nose tweezers are good for this.

squib said:

Here's some tips:
EML200F is the best cleaner as it also lubricates.
The best way to clean them is in an ultrasonic bath with a water / ammonia mix. However this will also clear out the white grease around the latching pin. So, I clean them in a ultrasonic bath, wash with clean water, blast out with an aircompressor, give a tiny squirt of EML or pro gold, THEN, replace the latching pin with a new one and add some white grease around the pin. It is time consuming and depending on how you value your labour, arguable just as expensive as buying a new one.
When replacing a broken latching pin be sure to look in the mechanism under a magnifying glass to ensure you get out any little broken
bits of the pin, needle nose tweezers are good for this.

Click to expand...

Thank you for detailed reply! That sounds very reasonable.
Couple of more amateur questions yet as we are finally starting to clean those things:

- what kind of water/ammonia ratio you suggest for cleaning and
- how long they should be kept in ultrasonic bath?
- does ammonia harm pcb's/components like resistors/LEDs? It would be great not to solder all of the switches out.
- is it ok to use PTFE grease like this http://www.motip.nl/index.php?page=23&id=751&cid=239 to lubricate the latches?