Luxman LV-92 rotary slide switch replacement HELP! - Page 1
Forum section: electronics / repair

author: Pexy13
author_rank: Regular Contributor
timestamp: August 03, 2025, 11:44:20 am
content: Greetings!My father has a luxman LV-92 stereo amplifier for his home HiFi system. He had it from new and now the rotary selector switch is acting up. When you set the desired imput you have to nudge it or tap it to get the full output. It doesn't work crisply and it became a real pain. I looked in the manual and opened the amplifier but I'm not 100% sure what kind of a switch I need. The one currently in the amplifier just states the Alps brand but not the model number, also in the service manual it only states SW201 and a item number that I can't find on the web.Can someone please help me identify what kind of a replacement switch I need? I'm wiling to go to the trouble of wiring a separate selector switch wire by wire because I don't think it's porbable that I'll find the exact replacement.I's definetly a 6 position but I'm not sure if it's a 2 or 4 pole swotch. By the schematic I think it's a 2 pole 6 position switch but I'm comfused by the number of pins(48) on the back side of the switch. They are probably doubled up but I could be wrong.Here's the link for the amplifier manual:https://www.hifi-wiki.de/images/e/e6/Luxman-LV-92-Service-Manual.pdfAnd the pictures of the pcb are inserted in the post.Thank you,Sven

author: Haenk
author_rank: Super Contributor
timestamp: August 03, 2025, 12:08:34 pm
content: I don't think it's broken. And there likely is no replacement to buy anyway.You might want to have someone check the solder joints on the PCB (or inspect them yourself with a magnification glass) - if the solder joints are fine, you are in for some Deoxit-action (or other contact cleaner). Might need a couple of applications. Protect the surrounding PCB from spills.Intermittent connection is not that far away from "working correctly again" on these things, it's just years of accumulated dust/dirt.

author: Sorama
author_rank: Frequent Contributor
timestamp: August 03, 2025, 12:08:41 pm
content: Have you verified the soldering of it?Did you try put some contact spray in the switch?

author: squadchannel
author_rank: Frequent Contributor
timestamp: August 03, 2025, 12:48:06 pm
content: many custom parts are used like the volume controls and switches of old Japanese-made audio equipment.These parts are completely discontinued today. it is extremely rare to find parts that can be used from other products.However, just because they are broken does not mean they cannot be used. They can be used after cleaning, but great care must be taken when disassembling them.small metal pieces that are used as contacts, and the claws on the housing can be broken if handled incorrectly.if you are not confident to disassemble it, use Deox-it.

author: robert.rozee
author_rank: Frequent Contributor
timestamp: August 03, 2025, 01:59:00 pm
content: Quote from: Pexy13 on August 03, 2025, 11:44:20 amthe switch's mechanical design is what i would describe as 'poor', i'm surprised that it has lasted as long as it did!it is a 6-pole, 6 position switch, but if you are not worried about the tape recording functionality, you can get away with just a 2-pole, 6 position switch. the relevant terminals are those furthest from the front panel, and you may be able to cut away parts of the PCB in order to fit a more conventional design of rotary switch.does your father ever use the amplifier to record to tape? this will dictate how you proceed with repair.cheers,rob :-)

author: Pexy13
author_rank: Regular Contributor
timestamp: August 04, 2025, 07:01:19 am
content: Quote from: Haenk on August 03, 2025, 12:08:34 pmThanks for the input. I'll check the solder joints and I'll try a contact cleaner spray on it. Hopefully it's all we need. Is there something I should look for in a contact cleaner when buying one? Quick google says we don't have deoxit here in Croatia.

author: Pexy13
author_rank: Regular Contributor
timestamp: August 04, 2025, 07:02:32 am
content: Quote from: Sorama on August 03, 2025, 12:08:41 pmI'll check the soldering joints. Should I reflow them anyway or leave them be if everything seems fine?

author: Pexy13
author_rank: Regular Contributor
timestamp: August 04, 2025, 07:04:14 am
content: Quote from: squadchannel on August 03, 2025, 12:48:06 pmThanks for the answer. First I'll try to use a contact cleaner on the switch befor trying to cleen the switch by disasembeling it. If nothing else works I'll try to do it that way. Too bad for the custom parts.

author: Pexy13
author_rank: Regular Contributor
timestamp: August 04, 2025, 07:06:38 am
content: Quote from: robert.rozee on August 03, 2025, 01:59:00 pmThanks Rob. Do you think it's a viable option to replace the switch with a different 2 pole 6 way design because my father never used the record to tape option. It is just used for playing music.

author: Sorama
author_rank: Frequent Contributor
timestamp: August 04, 2025, 07:22:41 am
content: Quote from: Pexy13 on August 04, 2025, 07:02:32 amYou can’t always see a bad joint: just reflow them by default

author: Sorama
author_rank: Frequent Contributor
timestamp: August 04, 2025, 07:24:14 am
content: Quote from: Pexy13 on August 04, 2025, 07:06:38 amYou don’t even have to relplace the switch: you can jumper wire those contacts.

author: Pexy13
author_rank: Regular Contributor
timestamp: August 04, 2025, 10:59:11 am
content: You can’t always see a bad joint: just reflow them by defaultAlright. I'll do that in a week or two when I get back home. I'll let you know how it turned out.

author: Pexy13
author_rank: Regular Contributor
timestamp: August 04, 2025, 11:00:26 am
content: You don’t even have to relplace the switch: you can jumper wire those contacts.You mean to set a fixed output with jumper wires instead of replacing the switch?

author: Sorama
author_rank: Frequent Contributor
timestamp: August 04, 2025, 11:10:15 am
content: Quote from: Pexy13 on August 04, 2025, 11:00:26 amYou mean to set a fixed output with jumper wires instead of replacing the switch?I’m not sure what you mean by output, as the switch we’re talking about is an input switch, no?That switch splits the signal to the low signal outputs for recording.If you don’t need recording, you can short some pins of that switch.That way it does not interfere anymore.Edit; after rereading your topic, it seems you still use different inputs.

author: Kean
author_rank: Unknown
timestamp: August 04, 2025, 12:31:23 pm
content: I don't think I have ever worked on any equipment with this type of switch, but I found a couple of blog posts describing cleaning and restoring them that might help.http://www.wiredwood.co.uk/wordpress/mission-cyrus-selector-switches-whats-inside/https://hoppesbrain.com/2017/06/01/how-i-clean-adcom-gfp-555-and-gfp-565-record-and-playback-switches/

author: squadchannel
author_rank: Frequent Contributor
timestamp: August 04, 2025, 12:39:14 pm
content: I don't know the mechanism of that switch, but the basic mechanism is the same. The important thing is to take lots of notes and photos.This is a video showing how to clean it(14min30sec). Mark's videos is always fun to watch.

author: Pexy13
author_rank: Regular Contributor
timestamp: August 05, 2025, 06:29:51 pm
content: I’m not sure what you mean by output, as the switch we’re talking about is an input switch, no?That switch splits the signal to the low signal outputs for recording.If you don’t need recording, you can short some pins of that switch.That way it does not interfere anymore.Edit; after rereading your topic, it seems you still use different inputs.Sorry yes I was thinking about the inputs but my mind already thinking that those inputs are "sent" to the output. To give you a solid answer yes we are still using different inputs for example the turn table or aux input. But we never use the tape function for recording, just the the basic audio inputs. Does this simplyfy replacing the switch with another one?

author: Pexy13
author_rank: Regular Contributor
timestamp: August 05, 2025, 06:30:59 pm
content: Quote from: Kean on August 04, 2025, 12:31:23 pmThank you! I'll check them out for sure because it seems like that will be my only plan B with that switch.

author: Pexy13
author_rank: Regular Contributor
timestamp: August 05, 2025, 06:46:36 pm
content: Quote from: squadchannel on August 04, 2025, 12:39:14 pmThank you. Really great video. Mark seems like a good and knowledgeable guy. If contact cleaner doesn't do the job I'll give it a go. My friend has a ultrasonic cleaner witch mark also mentioned. Do you think it's a good idea to try that as well? Im scared that it can be to agressive for the contacts.

author: Haenk
author_rank: Super Contributor
timestamp: August 05, 2025, 08:07:47 pm
content: Quote from: Pexy13 on August 05, 2025, 06:46:36 pmThe contacts are made of metal - impossible to damage with an ultrasonic cleaner.But really I would go with the soldering check and contact cleaner first - to be effective, one should disassemble the switch. And that's a risk, which should be avoided (as you will hardly find a replacement, if damaged).

author: tooki
author_rank: Super Contributor
timestamp: August 05, 2025, 09:52:43 pm
content: Quote from: Haenk on August 05, 2025, 08:07:47 pmUltrasonic cleaning operates by the process of cavitation — the same process that erodes the edges of ships’ propellers. So you most certainly can damage metal with ultrasonic cleaning, though it generally requires leaving it for too long.

author: Pexy13
author_rank: Regular Contributor
timestamp: August 06, 2025, 06:10:23 am
content: But really I would go with the soldering check and contact cleaner first - to be effective, one should disassemble the switch. And that's a risk, which should be avoided (as you will hardly find a replacement, if damaged).Yes I'll deffinetly first use the contact cleaner and reflow the solder joints.

author: Pexy13
author_rank: Regular Contributor
timestamp: August 06, 2025, 06:12:30 am
content: Ultrasonic cleaning operates by the process of cavitation — the same process that erodes the edges of ships’ propellers. So you most certainly can damage metal with ultrasonic cleaning, though it generally requires leaving it for too long.That's what I thought because I also saw what ultrasonics can do to a piece of aluminum foil. If the switch requires more cleaning I think I'll do it manually just to be sure.

author: elecdonia
author_rank: Frequent Contributor
timestamp: August 06, 2025, 01:23:47 pm
content: I desolder the switch and remove it from the PC board, followed by taking the switch apart in order to thoroughly clean all of its contact surfaces.Unfortunately spraying this type of switch with contact cleaner rarely works for longer than a few days or weeks.

author: squadchannel
author_rank: Frequent Contributor
timestamp: August 06, 2025, 01:36:44 pm
content: black dirt that comes from who knows where is messing the contacts.

author: Pexy13
author_rank: Regular Contributor
timestamp: August 16, 2025, 03:34:26 pm
content: Thank you so much for the help and guidance. I reflowed the pins of the switch and cleaned the switch with contact cleaner a few times and used a small brush inside with a vacuum cleaner to suck out any loose dirt and now it works like a charm. You can knock on the switch cap and the sound stays consistent and without any interference and noise.Cheers!

author: Sorama
author_rank: Frequent Contributor
timestamp: August 16, 2025, 06:35:50 pm
content: Well done!