Amplifier and Receiver Cleaning, Pots Cleaning, DC Bias Setting, Cracking Volume Control etc

[@Daltondoubledeuce]

Cheers from across the pond. Really digging your videos, clear, concise and explained perfectly. Well done you.

[@MichaelYates]

Thank you very much!

[@johnprice4819]

Thanks; really nice helpful demo!

[@D1N02]

Great video. I'm working up courage to open up my au-317

[@Akstergrind]

I know, scary innit? Good luck, mate!

[@kyleoboyle]

I'm gonna do that today with my au 317. Hope it fixes it and doesn't need to be serviced

[@RobD-jq7ry]

​@@kyleoboyle I've got a marantz 2385 i just picked up. I've got it open but I'm half paralyzed in fear. I don't want to cause any issues that do not already exist.

[@kyleoboyle]

@RobD8870 I say go for it if your comfortable with just taking out some screws and giving it a good spray. Was able to fix my au 317 instead of paying someone else to fix it

[@RobD-jq7ry]

@@kyleoboyle I appreciate the vote of confidence. Ive done it on other units but apparently the 2385 is much more intensive. You cannot clean the pots without completely removing the boards. The more I learn the more complicated its seeming. Alot of disassembly required. Im kind of bummed. I have the faceplate off the covers off etc and there's no good way to get to them.

[@gompsie]

My old Denon reciever takes a very long time to warm up before i hear sound coming out of it,and sometimes when i change channel i hear a loud static noise do you know what this could be,the reciever is over 20 years old belonged to my uncle who recently died so i really don`t wanne dumb that awesome reciever.......

[@MichaelYates]

What model number do you have?

[@gompsie]

@@MichaelYates The Model nr is : Denon AVR-2800 i took the dust out a couple of years ago but not as good as in your video,the problem is still there,thanks for your reply Sir.........

[@MichaelYates]

I was worried that it might be one of the newer models and TBH way beyound me as there are many microproccesors in this unit and a host of electronics. The static noise cound be a lot of things, one being the relay that might have dirty contacts though this is only one of many things, could be a noisey transistors, switching microprocceser, amoung others. The slow coming on is probebly down to same caps might need replacing. But its a monster unit with a lot inside and any repair would be quite expensive. Not a soloution really but you could try a factory reset this would be free and still worth a go though I very much doubt it would fix any issues, I am sorry I can not help any further than that. Reset can be found here manuals.denon.com/AVRX2800H/EU/EN/GFNFSYvyalrwrt.php

[@gompsie]

@@MichaelYates Thanks for your reply and yes when you open that reciever its more like a computer inside i will try to clean all components with isopropyl alcohol first and if that does not work i will try the reset thx so much for your reply........

[@MichaelYates]

@@gompsie Sorry I was not able to help any further. Best of luck with the Receiver

[@lavidaconkuro]

I have two passive stereo dali speakers snd a yamaha amplifier. All of the sudden, they sound mono, i pealed my speaker cables but thwy still sound mono

[@lshwadchuck5643]

Thanks for this. My Marantz receiver, I can see through the top grate, is DISGUSTING! I heat with an airtight woodstove, quite nearby, and I now feel like I can remove the screws, get the cover off and dust out the guts. Cleaning the contacts? Not so much. It works fine, I just think I should get the dust off the board.

[@georgescuovidiu1214]

Hello, I have the input selector from Yamaha AX870 very oxidated, is interrupting totally one channel power, so I just have sound in one speaker, if I move it left right the sound appear but dissapear, so I supose I need to clean it, what can I use to clean the boards from selector inside ?

[@MichaelYates]

I do not know that Yamaha, but I have had others and ones I have had in the past were the volume is a motorsied pot and one had a motorised input select as well. These can be more awkward to get the spray into, you migh find a hole in the switch casing to spray the spray into, though I would only use a little as could get into the motor if it is motorised. I have heard that sometimes the motor can cause the input select switch not to line up properly dues to worn cogs so that is a factor as well. But with a bit of luck with some cleaner ( I use WD 40 specialist contact cleaner ) on switches, you might get both channels to work. Other than that it might need a dismantel is possible or new assembly.

[@erictiscoff4296]

Can you please post a video of you setting DC bios on an audio innovations alto mk1

[@MichaelYates]

Unfortunately I do not have this amplifier, the little information I have on this is that use a DC voltmeter on millivolt setting connected across Resistor 21 and turn VR1 until 30 millivolts, do the same for other channel, R22 adjust VR2, this is from a 3rd party sauce that I found quite a while back, so cannot verify this

[@erictiscoff4296]

@@MichaelYates I have the schematic if that helps, I have tried what you say but the milli volts don’t seem to change

[@MichaelYates]

@@erictiscoff4296 I do have the diagram thanks, Would have thought they would have made some difference, but if not then , I see that you can adjust VR3 one channel and VR4 other channel until the voltage on the right of R21 / R22 is half the main voltage from power supply. This might help, but other than that without having the unit here I can not help much further, though I will grab one if ones going cheap at some stage.

[@erictiscoff4296]

@@MichaelYates yes read it through but can’t get 30mv may be the variable resisters need cleaning think I’ve read that only way to know is try I suppose,

[@MichaelYates]

@@erictiscoff4296 maybe need cleaning, is the amp working and what reading are you getting

[@tonypeppers4987]

hey michael, i found my rotel ra 810a is having trouble with any speaker i connect on the right side, after diagnosing with new rca to aux cords and speaker wire and different speakers, the right side will still give out and only high end comes out all fizzy. it all started when i unplugged the rca to aux from the back of the amp. i only use the Cd channel. Any suggestions before i open it up? thanks and great video ! cheers

[@MichaelYates]

Not an easy one, would be good to rule out the pre amp ic501 a NE5532AN which does both channels, which could be done by putting a signal pass this ic at coupling capacitor 506 to see if you still get the fizzy top end. if not then would probably be the ic This would be my first port of call, but could quite easy be a cap or transistor pass the pre amp ic stage.

[@tonypeppers4987]

@@MichaelYates thanks for the reply, it may well be a fuse that i noticed looks slightly burnt, 2 infact. ill have a crack at it today.

[@MichaelYates]

@@tonypeppers4987 Wish you luck, hope you get it sorted out

[@Orestis9]

Hi, this is a very informative video. I would like to ask for your help, because I 've dusted ( brush and air spray) and afterwards I ve used contact cleaning spray and it's been an hour now and not only it doesn't play but it makes weird noises ( humming and cracking) through the speakers. What has happened?

[@MichaelYates]

Hi,, If the unit was working ok before you started the cleaning and spraying then it might need a little more time depending how much contact cleaner you used. If the pots / switches have still got the liquid still inside them or some has got on to the circuit board then this will need to dry.

[@CM-dw3gh]

Hi Michael. I've realised before I do this I'm going to need the right clips, I'm presume they're smaller than average? Any details would be appreciated.

[@MichaelYates]

I found the easiest way was to buy these in the link below and attach one clip to the Amp board and other end clip to your meter lead prong. But be extra careful that nothing is shorting out any ware along the path of your meter lead and the attached crocodile lead , give yourself plenty of space and be wary of both leads while Amp is on. Of course a set that plugs straight into the meter would be better, but I bought 2 or 3 leads now and none fitted into the meter sockets. These leads I would have thought would be rated around 1amp at 250 volts ,, www.ebay.co.uk/itm/143969065011?hash=item2185399833:g:-pkAAOSwPPZgQm4H

[@CM-dw3gh]

@@MichaelYates I only got round to balancing the DC offset. Both are around the 6-7mv, as the left terminal was around 14mv before. This was just buy slotting in the prongs in the terminal holes and tightening the screws like you would bare speaker wire. I'll do the bias when I've grabbed another multimeter because like you mentioned in the vid doing the Bias it's easier. I've noticed the left speaker that had a lower volume output when playing music is now a level balanced sound with the right now.

[@CM-dw3gh]

@@MichaelYates yes these look a lot easier. The ones that came with the meter didn't seem to have much play in the mechanism whilst covered by the rubber. Very surprised they're not a common required lead to link direct to meter. Did you just bare the wire slightly for the clip?

[@MichaelYates]

@@CM-dw3gh The leads come ready made which saves any soldering, I just clipped the jaws of the clip on the pin on the amps PCB and a you can more the plastic sleeve right down to cover the jaws of the clip so there is no accidental shorting out

[@CM-dw3gh]

@@MichaelYates I've ordered some. But according to DLmanuals, there's 4 TP's (test points?)to clip the clips onto but they look like individual heat sinks. There does appear to be a resister next to each. Are these possibly the test points? (Nad c320BEE)

[@stevemumford6983]

Michael what is the name of the contact cleaner you use. Cheers Steve

[@MichaelYates]

Hi Steve, for just normal contact swiches I have been using WD-40 specialist Contact Cleaner as shown here wd40.co.uk/product/fast-drying-contact-cleaner/ also I have been experimenting using on pots as well, with good results. But normally use Deoxit F5 but its expensive for what it is I think thats why I have started experimenting with the WD-40 SCC

[@MichaelYates]

The one in the video is Rapid Electrical contact cleaner, which did a good job to on the switches

[@stevemumford6983]

@@MichaelYates Cheers Michael

[@Akstergrind]

Hey mate, like Alex below, I also bought a Rotel RA820 AX amp from eBay two weeks back, and it was great at first, but this morning it's dropping out and crackling very badly on both channels. I've tried it with a CD and it's absolutely fine, so I'm guessing it's the Phono stage that's at fault. Not really confident to crack it open, so it's going back, I'm afraid.

[@MichaelYates]

If fine on cd input and crackles on both channels on phono then a few places to start if willing to open up would be making sure the select switch is clean, could be dirty on the phono contacts, check the phono sockets on the back are making good contact inside and out, then the pre amp IC a NE5532AN, as this is just one chip doing both channels, but if easier just to send back then a refund and another purchase maybe the order of the day.

[@Akstergrind]

@@MichaelYates Thanks Michael, yeah I sent it back and I'm now looking at either a refurbished Rotel A11 or another (yes, I already have one but I love 'em!) NAD C326BEE. I'm using the one I've got in the bedroom at the moment, because it too has dropout and crackle problems, even though I paid to have it thoroughly cleaned inside. It hardly ever does it, and the sound it puts out is phenomenal! Anyway, thanks again, mate!

[@RicksRadioConversions]

Never use deoxit red if the potentiometer is carbon. Use the deoxit green.

[@MichaelYates]

Thanks for the information on which colour to use on carbon pots.

[@karlos543]

Think you'll find that is complete rubbish.