New here and need some help

[Daplumma]

New here and need some help .Updated pictures!

I am not an electronics guy.I know a lot of other stuff though and feel like an interloper here.I will gladly help out with any plumbing and HVAC issues.I can read ladder diagrams enough to troubleshoot control circuits on heat pumps and furnaces so I can follow basic electronic stuff.I can solder and desolder circuits in a pinch.Enough about that stuff.I have a L'equip mdl 528 dehydrator.120vac 4.5 amp 550 watts.I loaned it out to a friend and he got the temp contril wet and then broke it somehow.I have removed the control and wired the leads together so the unit works but it is stuck on high temp until I can replace this board.I cant seem to locate a place that will sell me the control.The official repair center has not responded to my inquiries for 3 weeks now even though its under warranty.Time to call in the interweb guys to help out.I hope I have payed it forward enough on other motorcycle,plumbing,fishing and old ford truck forums to have someone here help me out.Here are the pics of the board,the pot or variable resister or whatever it is is broken.I dont know the values or even how they rate these things or even the proper name for it.I would even be willing to mail this thing to someone to rebuild and pay for their time.Any help would be appreciated.
Joe
Looks like the writing says 38 5K

 

[Dean Huster]

You'll find them listed as "potentiometers" in catalogs, specifically as printed circuit board mounted trimmer potentiometers or some such thing. For what you have, about the only thing you need to worry about is the value (as opposed to power rating). Unfortunately, yours is smashed, so you can't measure it. If you have the schematic, maybe it will give you the value in ohms, kilohms (K ohms) or megohms (M ohms). Pots (aka potentiometers) tend to have values with either 1 or 5 as the significant digit, e.g., 500 ohms, 100 ohms, 5K ohms, 1M ohm, etc. You're not going to seem something like 60K ohms or 354 ohms.

Physical size will be another consideration since yours is PCB mounted. Digi-Key Corporation and Mouser Electronics are excellent sources for electronics parts here in the U.S.

 

[SABorn]

Do you have the rest of the pot, as sometimes the value is stamped on the rear of the pot.

Pure guess here......it looks like the resistor on the board is 1K5 (brown, green, red, bands) and dont see why the pot value will not be close to the resistor value, so am guessing something like a 1K or 5K pot.
Then again it could be any value.

 

[KMoffett]

Desperation? Do you have an Ohmmeter? I would measure the resistance, end-to-end, of the small arc of carbon element remaining on the right side. Estimate the angle of the arc in degrees. Divide 270 by that angle. Multiple the measured resistance by that number. It should give you a ballpark value.

Ken

 

[Daplumma]

Thanks for the replies.I will try to find the rest of the pot and post the pics.
Joe

 

[Daplumma]

I updated with pictures of the rest of the pot.Thank you
Joe

 

[ericgibbs]

I updated with pictures of the rest of the pot.Thank you
Joe

Hi,
Look thru these on this link.
Commercial Potentiometer Selection Guide

 

[Daplumma]

Thanks for the link.I'm not real sure what to look for.Maybe a 3/8 inch shaft with 5k resistance?It has 3 pins but I dont know the measurements.I am truly an electronics dummy and would take it to someone who knows this stuff if I knew where to take it.
Joe

 

[KMoffett]

Can you measure the pin-to-pin distance? Likely 2.5mm or 5mm. Mouser Electronics has some that will work.

Ken

 

[Daplumma]

Looks to be 2.5mm.
Joe

 

[SABorn]

Ok so you have now figured out its a 5K pot with 2.5mm pin spacings, which is what is often called a miniture pot.

You have the 2 important facts now so go shopping.

 

[KMoffett]

How long is the shaft from the top of the threaded collar to the end of the shaft? What is the shaft diameter? (you had said 3/"8", but more likely 1/4") Do you absolutely need the "splined" end on the shaft...to fit an existing knob...or could you use a different knob?

Ken

 

[Daplumma]

I think we had it covered now.I got a PM from a member here who offered to repair the board if I ship it to him and pay for parts and shipping.What a great place this is.Thanks again for all of your help.If anyone has any plumbing/HVAC questions I will be more than happy to try to help out.
Joe

 

[KeepItSimpleStupid]

Yep, the numbers look like 3/8 and 5K, so I'm in agreement. You can also assume linear taper.

You can substitute this 5K-Ohm Linear Taper Potentiometers - RadioShack.com from Radio Shack to see if anything else is damaged. Orient it the same way.

The hard part, then is figuring what matches up mechanically.

 

[KMoffett]

No, I'm not talking about the "38" on case. I need to know the actual diameter of the shaft that turns...the cylindrical section not the splined section. And not the threaded collar... although that might help too.

Like KISS said, you can kludge the radio shack pot in.

Ken