Model 14 parts

[Jim Easley]

Here are two possibilities for the pot replacement. Cost is 3~4 bucks each. Digikey and Mouser are on the internet if you need to do a lookup.

Digikey: pn# CT2153ND Mfg is CTS this one has a straight shaft.

Mouser: pn# 313-2401-50 This has a knurled slotted shaft.

[Richard C.]

Edrik,

Did you measure these controls with an ohm meter?
I can't see how all 4 of these controls have failed "open". The M.F. control is an EQ type control that has a limited effect on a small portion of the midrange. The H.F. control boosts/cut the high end. I noticed that my controls had little effect where I could use the EQ - AND my controls are good. What you should hear is a scratchy noise in the sound when adjusting these controls - IF they are bad (dirty).

The 4 digit number 79XX looks like a date code. 4 of mine are 79XX and 2 are 80XX. Looks like they bought a big batch in 1979/80.

You can use something like "PartsExpress" Tech-Spray #341-326 or #341-322. These won't harm plastic. You will have to almost flood the inside of the control for it to flush it.

Richard C.

[vn800_b]

Originally posted by Richard C.:
Did you measure these controls with an ohm meter?

<font size="2" face="Verdana, Helvetica, sans-serif">Sorry. I would not know how to use one. In any case, I will bring my speakers over to a friend who has restored other vintage speakers. I'm sure he has the appropirate meters and tools.

Originally posted by Richard C.:
I can't see how all 4 of these controls have failed "open". The M.F. control is an EQ type control that has a limited effect on a small portion of the midrange. The H.F. control boosts/cut the high end. I noticed that my controls had little effect where I could use the EQ - AND my controls are good. What you should hear is a scratchy noise in the sound when adjusting these controls - IF they are bad (dirty).

<font size="2" face="Verdana, Helvetica, sans-serif">Nothing happens when I try to adjust the controls. Perhaps the humidity here got to them?

Originally posted by Richard C.:
The 4 digit number 79XX looks like a date code. 4 of mine are 79XX and 2 are 80XX. Looks like they bought a big batch in 1979/80.

<font size="2" face="Verdana, Helvetica, sans-serif">I found some websites that explained the p/n codes. 137 7924 should mean made by CTS on the 24th week of 1979. The rest of the numbers are still a mystery to me. I can't see anything that would say 50ohms, 5 watts, linear taper, knurled, etc. unlike the p/n codes of CTS today.

Originally posted by Richard C.:
You can use something like "PartsExpress" Tech-Spray #341-326 or #341-322. These won't harm plastic. You will have to almost flood the inside of the control for it to flush it.

<font size="2" face="Verdana, Helvetica, sans-serif">Awesome. I'll try it out!

Thanks!!!

[Richard C.]

Edrik,

Quite often a manufacturer will use their own code to describe what the part actually is. IC chip makers will often sell chips with "in house numbers" to a company to load in their circuit boards. This practice makes them proprietary. You can't easily buy them at your favorite supplier.

I measured the resistance of those controls at 50 ohms, and I set them at 1/2 of their rotation which measured 25 ohms. This is a linear taper. I guessed 5 Watts or so from my experience.

When you re-install your crossovers, you might want to tape up one of the pins on the lamp (red & blk wires). These pins are easy to push together when mounting in the thick front panel.

I like the detail of your picture. You have a later crossover with the 10uf "C4" cap.

Richard C.

[vn800_b]

thanks! here's another view.

[thinking]

A highly rated line of cleaners is made by Caig. They have several cleaners under the name DeOxit that work well for cleaning moving contacts, and another product called Cailube fro lubricating them after they have been cleaned.