Strange Potentiometers for Electro-Acoustic Yamaha CN-525E - Page 1
Forum section: electronics / repair

author: paul_g_787
author_rank: Frequent Contributor
timestamp: May 28, 2022, 05:17:04 pm
content: Hey everyone! I have been dropped by a friend his Yamaha CN-525E electro acoustic. I am told it is about 35-40 years old the fault being no sound.I had to initially fix a corroded 9V battery terminal, now am able to connect it up and try it but I have found that the sound coming out is super quiet and is only audible at full volume with gain maxed on my Marshall MG30. Compared to my electro acoustic I would say this guitar is 2 - 5% the volume it should be.I believe the problem is with the three potentiometers (Bass, Treble and Volume) these read as marked across the outside two pins however I cannot get any readings at all on one and the other two including the volume pot read over 20MΩ so I suspect the wipers are corroded or not contacting.But they are a very strange type. Can anyone help me identify these pots and maybe help me in finding replacements?They push in and out so that they sit flush with the body of the guitar and you just click them out when you need to adjust them. Quite a good idea actually until you need replacements.(The green wire is where I soldered to the middle pin to get my test leads to clip on).They aren't the switching type of pots. The guitar has a 3-pin TRS jack which acts as the power switch.

author: paul_g_787
author_rank: Frequent Contributor
timestamp: May 28, 2022, 05:18:00 pm
content: Side view of where the pots sit.

author: Audiorepair
author_rank: Frequent Contributor
timestamp: May 28, 2022, 10:27:25 pm
content: It is extremely unlikely you will find these pots.You need a plan B.

author: strawberry
author_rank: Super Contributor
timestamp: May 29, 2022, 06:14:39 am
content: alps rk097 Potentiometer Push-Lockhttps://eu.mouser.com/ProductDetail/Alps-Alpine/RK097111TD2M?qs=Xb8IjHhkxj6Mc7WhZQi9kQ%3D%3Dhttps://www.aliexpress.com/item/32943898772.html

author: paul_g_787
author_rank: Frequent Contributor
timestamp: June 04, 2022, 01:16:13 pm
content: Unfortunately those ALPS pots would not be compatible.I went with a plan B;I decided to simply bypass the pots with resistors. This means the bass/treble or volume would no longer be adjustable however the guitar is at least useable.

author: strawberry
author_rank: Super Contributor
timestamp: June 04, 2022, 07:27:51 pm
content: precise model number : RK097111Tchinese copy is reason why it failed so fast

author: 2N3055
author_rank: Super Contributor
timestamp: June 04, 2022, 11:43:42 pm
content: Quote from: strawberry on June 04, 2022, 07:27:51 pmYes, damned Chinese shit pots, they failed after only 35-40 years...To OP: just replace them with normal pots...

author: CatalinaWOW
author_rank: Super Contributor
timestamp: June 05, 2022, 04:41:17 am
content: It is worth a try with DeOxit or similar contact cleaner.

author: Audiorepair
author_rank: Frequent Contributor
timestamp: June 05, 2022, 09:09:56 pm
content: Given a bit of practice, it is not impossible to totally disassemble potentiometers and put them back together again.They usually have tabs that you can bend back and get the thing apart.During this process you mostly find out why the potentiometer could never work again, but occasionally you can clean and furgle it without damaging it too much, and it will work again.It's best to mark or photograph the parts before and during disassembly, as often there are multiple ways to reassemble it, only one of which is correct.Since you have nothing to lose, I would give it a go and learn something.Edit: Oh, and definitely try soaking it with De-oxit etc first if you can get it in there.

author: Audiorepair
author_rank: Frequent Contributor
timestamp: June 05, 2022, 10:53:56 pm
content: https://www.hotroxuk.com/caig-deoxit-d100l-2c-squeeze-tube.html

author: CatalinaWOW
author_rank: Super Contributor
timestamp: June 06, 2022, 03:33:13 am
content: These pots are riveted together. Drilling out the head on the front end will allow them to be pressed or punched out with the appropriate pin punch. For most people it is easier to replace the rivets with an appropriate size nut and screw. I wouldn't be afraid to try, my success rate with this type of construction is pretty high. But I would still try contact cleaner first. It works sometimes, though less than half the time in my experience. It doesn't ruin the pot if you have to go further to fix it..

author: paul_g_787
author_rank: Frequent Contributor
timestamp: June 15, 2022, 12:20:07 pm
content: I did try to find replacement pots but the issue is the PCB footprint does not seem to be match anything I could find.This is an issue because these three pots hold the entire assembly into the guitar.I tried deoxit and other cleaners but I think the wipers are just gone! There is absolutely no reading on two of the pots and 10MΩ on the other.I believe the owner stored the guitar in the loft for the last 10 years. The guitar bag smells a bit mouldy. Probably didn't do it any favours.He seems perfectly happy with the bypassed pot fix for now. Maybe I will re-visit this another time but he at least can play the guitar through the amp now.

author: barry21
author_rank: Newbie
timestamp: September 13, 2024, 02:33:41 pm
content: hope you can post this if you think it could help someone. . it is the preamp for the yamaha CN 525E with part numbers.

author: coromonadalix
author_rank: Super Contributor
timestamp: September 13, 2024, 02:52:36 pm
content: some web say RK097111T is obsolete .... but we have other models who dont have the slide rodmaybe you'll have to resort to old chineesium once again ...or bypass everything to have a flat sound response and the guy use an external correction device ....many "old" car radios had them but finding them and having the same footprint ....

author: wasedadoc
author_rank: Super Contributor
timestamp: September 14, 2024, 05:40:31 pm
content: I was asked to refurbish a 1980s vocoder. 14 channels. Each channel contained a current output chip with a 100k pot as its only load. Following the alignment instructions I found I could not get the output levelsdownto the necessary levels. Found that the end to end track resistance of all 14 pots was greatly in excess of the marked 100k. Some more than 1M. Had to replace all 14.The originals were a well known at the time brand.