33 Repair

[Yowie]

I'm a new forum member. I hope you won't be mad at me for saying that I use a 33,303&FM3 in the garage as I like the radio while working.

It's not as awful as you imagine, the boxes are in a stylish glass fronted cabinet and my speakers are wall mounted.

My problem - the potentiometer that controls on/off and volume is very crackley and takes a bit of jiggling before I get the right vol in both channels. Not unusual.

Can ayone advise as to the best repair or cleaning(?) solution. I'm sure I'm not the first to ask. Thank you
Howard Yeomans
UK

 

[quadanasaziland]

Hi Howard!

I think you are a bit confused, this group is about quadraphonic and multichannel gear. Glad you joined and I think some of the guys could help with your problem. Most audiophiles are alergic to what we do here!

 

[sqdave1975]

I'll probably get flamed badly for this now but, here goes......for crackly pots I usually find that normal WD40 in an aerosol is more than adequate. This is of course assuming that, like in most cases, there are openings in the pot that allow you to get the lubricant into the carbon track/wiper assembly.
My defense - I've got loads of vintage gear in the loft that gets pulled out from time to time for testing/routine powering up - so far I've had no ill effects whatsoever from using WD40 - just clean, smooth, noise-free potentionmeters-even after years of storage. You could always try the proper stuff - Servisol Contact Cleaner Code: JP17T from Maplin Electronics (branches all over the UK) Price: £2.49 will do just fine. www.maplin.co.uk
Also good for relays, selector switches, contacts, etc. found in all vintage gear. - good luck!

 

[Quadwreck]

WD-40 contains oil, which will lubricate wonderfully and later turn against you. As the oil ages, it thickens, and will not allow your contacts to contact. It will also act as an attractant for dirt in an unsealed potentiometer. Spraying more in will temporarily thin the old oil, but you're simply building up more residue. When I get in units that have been "maintained" this way, I often have to replace the pots as the gunk can't all be extracted after an uncertain period of time.
If you don't have a spray can of a non-residue cleaner, pure alcohol and an eyedropper will work.

 

[sqdave1975]

Philips Contact Cleaner 390 DCS (BLUE) in an aerosol contains no oil and is also highly recommended, but might be slightly difficult to find. Not expensive though.

 

[Yowie]

Thanks everyone, forgive me for blundering into your quadraphonic forum with a querie about Quad stereo. Oop is that a rude word ;-)

I'm going to proceed with first desoldering the pot, then I'll immerse and rotate in some solvent - cellulose thinners for my spray gun. Hopefully that'll clean it up really well without any residue.

I'll post the results to wrap up the thread.

 

[The Quadfather]

Oil is not a bad thing on a mechanical sliding part as long as the part is used in a clean environment. I find that a good tuner cleaner (avoid the blue foam goo) is excellent. It is similar to WD40, but isn't as heavy on oil, and having more solvent. In cases where the pot is almost gone, sometimes 3 in 1 oil can get a little more life from it. It is only a last resort, because it doesn't spray away the dirt and old cleaner when you use it. Aerosol cleaners do, and do it quite well. especially when you can get at the pot through an opening. Always operate the pot through it's full range when cleaning, in order to loosen any dust in the wiper path. I have treated my gear like this since the end of the quad era, and haven't had to replace a pot yet. I would suggest that pots be cleaned at the first sign of trouble, and any time the equipment is opened for any reason. Also, with pots that are soldered directly to circuit boards, look for cracks in the solder in the form of a circle around the pin. This is a common source of trouble, and can be easily repaired by resoldering. Removal of old solder is recommended using solder wick or a sucker. If the environment is particularly dusty, then use a dry solvent with no oil. However, if the environment is dusty, perhaps it is not a suitable environment for quality gear.

The Quadfather

 

[dennisnate]

Yowie - There are two Quad 33s on the bay right now. Buy 'em and join the Quad Squad! Quad Quads would be way cool!

 

[AllAroundSurround]

Buy Both and add it to the first quad and have 5.1 - Tri-Quads!
Rob

 

[Obbop]

And I'll be the first to add the obligatory mention of quad quads!!!!

burp.

 

[AllAroundSurround]

<blockquote><strong><em>Quote:</em></strong><hr>Quad Quads would be way cool! [/quote]
Sorry, but someone beat you to it!
Rob

 

[Yowie]

Thanks for the input. The desoldering went okay and I managed to immerse the pot in a bath of solvent and sweep through the whole range fine. Left to dry for a day and reinstalled. Perfect results, so far.

Re: Quad and 5.1 Quads - I have trouble enough from my girlfriend when justifying more hardware and having just biamped my Audiolab system, well my "credit's" all spent up. And the wires, oh God the wires. I think wires are less well received than the actual boxes.

Thanks again, Howard Yeomans

 

[AllAroundSurround]

They make speaker wire that can go on the wall and be painted , and can't be seen! It's flat and is great for hiding the wires!
She'll never know!
Rob