Left channel rec in dead, not recognizing HDD

Hi everybody, long time lurker, first time poster.
First of all just wanna introduce myself. Been DJ'ing for about 10 years & been into beat making for about 4 or 5 years now. I really like the forum & I'm looking forward to becoming an active member. I mostly (try to) make boom bap & I'll be posting some beats up soon.
Iv had my second MPC (2500) after graduating from a 1000 for about a year & its started developing some problems.....
First the rec in left channel has stopped working properly & now the MPC has stopped recognizing its hard drive. So I'm reduced to recording in mono & saving to CF card.
Could these problems be related somehow?
There is a tiny amount of signal coming through the left input & I can increase it by turning up the rec gain but this of course distorts the right hand input.
So maybe a new encoder would fix it?
Also, Iv tried several HDD's in the machine but no luck. The MPC just freezes on start up but is fine without a HDD installed.
Im using the free JJOS. Iv tried re-installing it & even resetting back to factory settings.
Any ideas on what to try to fix this? I am ok with a soldering iron but just wanted your input before I start ordering parts & taking things to bits. Iv checked the right hand PCB & all seems ok so Im a bit stuck.
Sorry for babbling but any help with this will be appreciated.

HAve you tried different cables and mixer into the input? To rule out the fact that it could just be the cable going from the record inputs of your mpc to what ever(dj mixer?)

Maybe the harddrive tray is dislodged? Happened to me once..
Have you taking it apart to check?

I doubt it would be related.

I'm recording from a DJ mixer but Iv tried a different mixer & cables with no luck.
Iv also taken the hard drive tray out & tried 3 different HDD's in it with no luck. Could it be the connector assembly that's gone faulty?
Thanks for your input though man.

Left input/output is somthing that has been popping up from time to time in here more frequently. I dont wanna give you false info so browse this forum, I think someone posted solution to the problem. If memeory servese me right there's some kind of build up accumulates over time causing this. You'll have to the mpc apart and look at that pcb board.

Have you verified HDD is still in good working order, check HDD connector inside the mpc and HDD itself

konc3pt wrote:Left input/output is somthing that has been popping up from time to time in here more frequently. I dont wanna give you false info so browse this forum, I think someone posted solution to the problem. If memeory servese me right there's some kind of build up accumulates over time causing this. You'll have to the mpc apart and look at that pcb board.

Have you verified HDD is still in good working order, check HDD connector inside the mpc and HDD itself

I have had the right hand PCB out & all look to be ok (to my eyes anyway)
Could it be the dial itself thats dying?

Also, I haven't checked the hard drive connector yet though. I'm gonna try take it out tonight & give it a clean with some contact spray.

Its just strange to me that both these problems occurred at roughly the same time.
I'll keep tinkering & see what happens.
Thanks for the input

do you have cd-r installed in your mpc ?

konc3pt wrote:do you have cd-r installed in your mpc ?

Yes I do. All seems ok with it though.

Good news!! Turns out one of the contacts on the HDD adapter was pushed down. I popped it back into place & its now working like a charm! I don't know how I didn't notice it before but hay ho. I'm happy its working again.

Now, if I can only get my L-in working...........

good to hear, as last resort you maybe looking at taking it electronics shop to get it fixed, if you're located in U.S forat can fix it...I had one 2500 that wasnt outputting any sound at all, turned out it was bad resistor...cant remember what I paid exactly but with shipping it came out to $300-350

Nah man I'm in the UK. I'm gonna keep tinkering with it though. I have a friend with a multi-meter & a steady hand who's gonna take a look at it for me.

if your friend is somewhat familiar with electronics and follows the signal path with multimeter should be no problem finding the root cause of the problem..

I'm guessing you already checked to make sure nothing is stuck inside the jack port and inspected the pcb visually for problems

konc3pt wrote:if your friend is somewhat familiar with electronics and follows the signal path with multimeter should be no problem finding the root cause of the problem..

I'm guessing you already checked to make sure nothing is stuck inside the jack port and inspected the pcb visually for problems

Yeah he does car electronics for a living & we have checked the PCB & all seems ok. That's what got me thinking maybe its the encoder itself? Even though the dial still controls the right hand volume ok, just nothing coming through the left. Im sure the multi meter will tell us.
The jack input seems clear but I'll double check it tonight.

From what I observed here, if your stereo outs start to go wanky most of the time it is volume gain pot that need replacing.

Maybe it is the same way for rec gain, this is probably more used than volume gain so I'd say it's a good possibility it's just the encoder. It's $16 part and I think it'd be worth a shot.

If your internals was messed up by feeding too hot input in, it is unlikely that someone would be sampling using just one input, both your inputs would be messed up.

I think gain encoder would be good place to start and probably cheapest