Laney Hardcore max hcm 60r

[merryoldp]

Hello peeps, Bob here 1st post, My mates son has put this amp in my hands for fixing!
(I rewired his dads mates motor bike, so was asked to try mending this amp!) (yes I know)
The 'crunch' is the problem, when the button is pressed it becomes very noisy, its not a buzz as such,
more of a deep hiss, it gets a lot worse when turning the 3 crunch tone pots.
Nice and clean when the crunch is off, but the 3 tone pots on the 'clean volume' don't seem to do much .
I was told it was a mucky pot. I replaced the 100k 2 gang pot with 1 from Maplin
but it wasn't a quiet component! the new pot made it a lot worse.
does anyone know where to buy proper alpha pots in UK?
I'm starting to think I will reassemble the amp and advise him to take it to the shop for repair.
These tiny surface mount components are a pain in the rear!!!

[J M Fahey]

Just out of the top of my hat, those amps use a CMOS digital inverters pack (CD4049 or 4069 or something like that) as amplifiers and clippers in the dirt channel.
It should be a 14 pin IC, labelled as such, which hopefully is regular through hole size.
Laney is known to mix both technologies in the same board.
Substituting it with a new one might be the ticket.
Cost is nil, a few cents.
If it's the SMD version, sorry, it will complicate matters, in my view, simply because of the size.
Edit: I forgot, there is also a TL072 which is also part of the first gain stage in the distortion channel (I repeat, I´m quoting by heart), maybe it's worth replacing it too.
Not many more active components there besides them.

[merryoldp]

Laney Hardcore max hcm 60r

thank you very much for the tip. It does indeed have a CD4069, on the board, and
It is a mix up of SMD and 'normal' through wire components.
I will order the chip and replace it. If this a common fault
would it be practical to add a 14 pin socket for future maintainace / repairs?
As an aside. All the pots seem mucky on my old scope, so have ordered a full set.

Thank you for your help. Bob

[J M Fahey]

No, it´s not a common fault, but in this particular case reasonably matches your hiss problem.
I *much* prefer soldered connections to any kind of connector.
Here you have the HCM120 ; the preamp should be basically the same
hcm120r_h.pdf
Good luck

[merryoldp]

cheers i'll not bother with a socket then. thanks again Bob

[mozwell]

hcm 60R service manual

If you are replacing the 4069, it must be the "U" version.
If you replacement part is (say) CD4069BE, it wont work, you must use CD4069UBE it is the "Unbuffered" version of the chip.

use a signal generator, input a 50mVAC signal & follow the signal through the amp if replacing the 4069 doesnt work

[merryoldp]

wow timing, the eBay seller just messaged me to confirm my order, I had not put either CD4069UBE or CD4069BE saved my bacon there, well a couple of quid and a few days wait on the post, cheers Bob

[n3tw0rk3r]

Hi there!
Sorry to resurrect this old thread but I'm having an issue with a Laney HCM60B. After connecting my bass the sound starts to fade out, dissappears completely, then it cracks and the sound comes back and then it starts to fade out again...

Does anyone have experienced an issue like that before? Also does a kind soul in here accidentally have the schematics for the HCM60b?

Thank you, Tom

[oc disorder]

Hi Tom & welcome to the forum

You will find the circuit here at Black Magic Amps

http://bmamps.com/Schematics/Laney/L...ice_Manual.pdf

The first thing I check in those is the power supply... the two zeners and the 470ohm resistors D9, D10, R22 & R38.

They get hot and melt the solder holding them on ! If you have the chassis out try tapping the area with an insulated object a stick - a biro etc.

You may find it comes and goes as you whack it ! If that is the case you may need to reinforce the connections and tracks around that area with thin stiff wire.

[n3tw0rk3r]

Hi oc disorder,

Thank you so much for the quick reply! I will try that.

Tom

[n3tw0rk3r]

Hi oc disorder,

Just wanted to let you know that the amp is working again. I had to facepalm myself very hard after measuring up everything (and all was fine, duh) and then finding that the jack socket metal lip of the FX send was dirty. Cleaned it up with contact cleaner and voila -> happy amp and owner.

Thanks again for your quick reply.

Greetings from the Netherlands,

Tom

[oc disorder]

Ahh Good ! Glad you found it I 'spose I should have posted this as step 2!

The Dreaded Switching Jack Problem

http://music-electronics-forum.com/t28549/