RM4 Schematic

Hey.
Just got an used Rm4 and its acting up a bit. i was planning to check it out myself, but i can`t find a schematic for it.

Does anyone here have it,? i would be ever so grateful

cheers

no one ?

My tech is in search of that too. If he gets it, I will try and get it to you.

Thank you so much

It`s some component that i see needs change, but also when i play through my rig ( rm4 into Mesa 2:90 ) its almost like i dont have any presence at all on any of my modules.. they sound so much more alive in my RM100... I dont think it`s the mesa that much , cause i have used that with my axe fx ultra and also a studio pre before with no trouble at all..

if anyone may have an idea, let me know.
And yes i have changed ALL the tubes in the 2:90 , RM4 and modules...

One other thought would be to test the RM4 through the loop return on the RM100 just to confirm where the problem is.

Yeah i Just did that , and some of it is the Poweramp, but i opened the RM4 and saw a component that i think may be broken ,or braking.. looked like some bad work in there. .. ill see if i can get a pic up here for you Guru`s to tell me what you think

here is one of the parts that I think i should change ...

I have schematics now. Hit me with you email and I will foward them to you.

Change that cap.. looks suspect and maybe bend it away from the PCB board post bolt. (arching if too close, I saw it once in one of my DIY plexis where I was too close) Just a suggestion though, can't hurt to swap a cap.

thank you. yeah I`ll swap that out.. and it looks like a bad job whoever did that before. the legs are so long out and stuff.. i suspect it has been changed before to..

Also possible it is a cold solder joint.. someone tried heating from the top and jamming the cap in rather than going from the underside of the board. (which to do usually means getting that PCB up)

Oh, while you are in there, check the values by your presence pot. Earlier Randalls were much darker than the later revision presence boards. There are a few threads on this forum on that very subject... i think they are in this section. JF outlined the right values.

See here: http://mtsforum.grailtone.com/viewtopic.php?t=15167

thanks but there is no Presence on the RM4 ? only master volume and Paralell fx mix ?

or am i missing something ?

ah i forgot to say that im using the Randall RM4 with a Mesa boogie 2 :90

BigBrewtus said:

I have schematics now. Hit me with you email and I will foward them to you. Thank You!

Click to expand...

I would like the schematics for the RM4. Thanks. [email protected]