Rgvkiwi Posted May 10, 2009 Share Posted May 10, 2009 Hi Guys I am new here but have been reading for a few months. Feel free to redirect me if i am in the wrong place..... I have a VJ Junior v2 combo that i replaced the R1 resistor as is suggested quite succesfully plus a few other minor mods. With no issues, amp improved nicely. As i like to run instereo i recently bought a VJ Junior v3 head and cab, nicely opens up the sound and is "louder, clearer" sounding. Unfortunately last night i tried the same R1 replacement and now have no sound what so ever, every thing powers up normally but but not even a crackle, when touching guitar lead, no hum, hiss, nothing. It is a 1w 1M resistor and is larger than the others on the board (which i presume are .5 w...?) Anyone here have any electronic experience that could suggest where i start? any suggestions would be much appreciated! Regards Mark Link to comment Share on other sites More sharing options...
m-theory Posted May 11, 2009 Share Posted May 11, 2009 I was under the impression that the V3 amps had that part right, and there was no need to mess with it. Irregardless, you've obviously got something not right, because swapping a 1m resistor for another 1m resistor surely isn't going to make the amp go dead on its own. Check the connectors to make sure you plugged them back in. Seems as though that could be a fairly common mistake. Check that you've got both tubes glowing as well, as you may have also forgotten to put one back in, or didn't get it seated properly. Also, remove the fuse from the orange wire, sand both ends, and re-install. Make sure your speaker cabinet is plugged in. Those would be the most obvious things to check for that I can think of offhand. If it's not one of those, check over your R1 work carefully. Link to comment Share on other sites More sharing options...
TWANG Posted May 11, 2009 Share Posted May 11, 2009 Know what I did .. more than once.. put in the R1.. then forgot to reconnect the thing. *G* stupid green boards, it's their fault! TWANG Link to comment Share on other sites More sharing options...
Rgvkiwi Posted May 13, 2009 Author Share Posted May 13, 2009 Thanks Guys, Got it going now. One of two things happened (neither show me in a good light :D ) 1/ WHen i removed the original R1 it stuck and when i used force to pull it out damaged the trace on the PCB. So when i replaced the first one i put in i skipped the track and soldered straight to the leg of R2 and Valve 3. 2/ Upon completion of the above i noticed the top of the 12ax7 valve was smokey. I may have broken the 12ax7 valve when manouvering the board so as not to unplug any leads ( this would surprise me, as i am not generally that ham fisted!). To cap this whole thing off, Mtheory is right, the bloody thing was already a 1m resistor in the first place! Thanks for your input guys. I'll be more carefull next time. Link to comment Share on other sites More sharing options...
m-theory Posted May 13, 2009 Share Posted May 13, 2009 I'll be more carefull next time. None of us would ever learn much of anything by not making mistakes from time to time. Link to comment Share on other sites More sharing options...
Rgvkiwi Posted May 14, 2009 Author Share Posted May 14, 2009 Cheers! And i agree, those green boards look like pretty good quality BUT can't see a damn thing on them. Might wait a while before i start messing with it again. Pretty keen to try the "Fender" mods. Also, can the V2 combo be wired to use the 1x12 Epi cab (it is 16 Ohm) where as the combo is 4 Ohm. I believe you can sort out the unused wires from the Output Transformer to create an 8 Ohm Output but not sure of a 16 Ohm...? Link to comment Share on other sites More sharing options...
Eracer_Team Posted May 14, 2009 Share Posted May 14, 2009 Link to comment Share on other sites More sharing options...
Eracer_Team Posted May 14, 2009 Share Posted May 14, 2009 Ver1 combo had 4ohm jack and 8ohm hidden (no 16ohm) Ver2 combo 'early version2' had 4ohm jack and 8ohm hidden (no 16ohm) these are pretty rare birds. Ver2 como/Ver 2 head/ Ver 3 4/8/16 ohm all on jacks Link to comment Share on other sites More sharing options...
SlagJones Posted May 14, 2009 Share Posted May 14, 2009 Ver2 combo 'early version2' had 4ohm jack and 8ohm hidden (no 16ohm) these are pretty rare birds. Does that make it anything special or give it any added value for being rare? I have a version2 with only the one jack. OR does that just mean there were only a few made before being upgraded to the 4/8/16 jacks? Link to comment Share on other sites More sharing options...
Eracer_Team Posted May 14, 2009 Share Posted May 14, 2009 Just means Epip was just using up the last of their stock before moving on. Link to comment Share on other sites More sharing options...
Rgvkiwi Posted May 14, 2009 Author Share Posted May 14, 2009 So from what i have been reading lately a 2:1 ratio of amp to speaker load would mean the 8 ohm output to the 16 ohm speaker is okay or not? SlagJones, it just means we got the short end of the stick by the sounds of it. However that V2 combo is WAY easier to see the circuit board on for modding. Oooh, another question, does anyone have any tips for removing the glue that is all over the R9 resistor and some of the caps. It stopped my modding in its tracks as it is covered in what looks like hot glue gun glue..... Link to comment Share on other sites More sharing options...
TWANG Posted May 14, 2009 Share Posted May 14, 2009 You have to just pick at it. I found that using a small screwdriver to gently push at it... all around it's edges.. eventually gets it moving off..then you can pull it off with a needle nose pliers.. so long as you don't pull on the component. so just gently pushing at it, it peels back.. get it off the resistor or cap gently... and then pull. those green boards are tough.. the solder pads lift pretty easy.. so be careful with the heat and be sure they are reconnected. tWANG Link to comment Share on other sites More sharing options...
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