Triaxis loop is not functional

[disassembled]

Has anyone had a problem with their loop besides fatboy? I didn't even realize I had a problem until I tried to send a signal to my effects processor and found out it didn't work. I think I have some LDRs that went bad since they read infinity on my ohms meter where other diodes/LDRs read fine. For those that do not/have not used their loop I suggest you plug a cable into the send and return jack to make sure everything is ok.

Instead of being loopless I just jumpered all of the connections for the send and returns so the loop is functional. The weird part is that I can still turn the loop on and off with all of the LDR's for the loop bypassed. I am going to order 1 new LDR to see if that is my problem.

If anyone has any helpful it will be greatly appreciated. Oh, and please don't recommend the obvious, meaning don't recommend that I send it to Mesa for repair.

 

[disassembled]

To anyone that is following this:

I did some testing of the LDRs for the loop (this is what Mesa is using instead of relays) and found that 2 out of 5 were not functional. I am ordering 5 new ones as I do not have faith in the parts that were picked. These are the parts I am going to order:

http://www.alliedelec.com/Search/ProductDetail.asp?SKU=980-9951&SEARCH=vtl5c9&n=&MPN=VTL5C9&DESC=VTL5C9

So for $15 and bit of knowledge gained I feel this was a worthwhile troubleshooting endeavour.


I hope the new LDRs fix the loop switching.

 

[triodal]

How do you check the ldr with the meter?

 

[disassembled]

LDR's are ****** compared to relays in that they always have resistance on the switching side. A relay would either be zero resistance or no connection. When activated the LDRs will have about 200 to 400 ohms of resistance on the "cell" side and when off they will have about 50M ohms. The LED side should test at about 600 ohms (this is a standard Diode test). You must have the power on to test. If you are just curious and do not have any electrical experience then I whole heartily have to not recommend you try to test. If you are aware that there is upwards of 400 volts DC inside that is waiting to meet you and you take necessary precautions(either supervision or preventive) then you are taking this into your own hands.

This can be dangerous stuff and sometimes it can be too late to learn the hard way.

http://www.alliedelec.com/catalog/pf.asp?FN=1564.pdf

This is a catalog page with a similar opto isolator that was used in my Triaxis.

BTW are you just curious or is there a problem with your gear?

 

[Rayder]

blank

 

[Tuna141]

dissassembled,

Did you end up replacing the LDRs on your Triaxis with the PerkinElmer VTL5C9? Is this LDR compatible to the ones that Mesa used in the original design? Did it fix your problem?

I just found that I have a problem with my loop - one side works fine, but the other has low output and is humming/breaking-up. I'm going to troubleshoot the problem it this weekend and came across your post.

Thanks.

 

[disassembled]

Yeah the LDR's are the Vactrol VC9's and i ordered them from allied which was the cheapest solution. Search allied for optocoupler and you should get some hits. You should test your signal path and the resistance on the LDRs before desoldering them from the board. My loop was not functional because the LDR's for the Send jack were not functional. You can get the schematics for the loop section on the yahoo group for the triaxis. I suggest do some really in depth troubleshooting before you go buying and replacing parts. One thing to do is to use an MP3 player to the return jacks and see if it is still waek on one side.

If you have a scope or other test gear and a good knowledge of electronics you shouldn't need much help. If you don't have a lot of background then you should be cautious. There are some serious voltages in there (400+ VDC!!!) that can kill or seriously injure yourself. Also, you can seriously ruin the preamp if you ruin the traces on the PCB so be extremely careful with your soldering iron (use a 20-25 watt at the most). As long as the switch logic is good (ie the digital side is working properly) you shouldn't have any issues.

Greg

 

[Tuna141]

I hadn't used my Triaxis for a few weeks and discovered the problem late last night. My rack is a little complicated (Triaxis, Egnater IE-4, GCX, G-Major, 2:Ninety), so I haven't absolutely confirmed that it is the Triaxis. But I did rule out the power amp, and have narrowed the problem down to either the Triaxis or G-Major or a relay in the GCX, and at this point I'm just guessing it's an LDR on the Triaxis.

I was able to download the schematic for the loop circuitry in case I find that it is associated with the Triaxis effect loop. I plan on investigating this problem further this weekend, and I'll post my findings.

Thanks for your help.

Rob

 

[Tuna141]

Well, I trouble-shot my rack last night and determined the problem...the good news is that it's not my Triaxis. The bad news is it's my G-Major. Luckily, I have a 2nd G-Major, so I'm back up and running - I just have to transfer my presets from the defective G-Major to my good one.

I've got an email into TC Electronic to see what they have to say about the G-Major problem....

 

[disassembled]

I stopped using effects so my effects loop repair hasn't done me much good anyway other than for resale value.

I have taken a minimalistic approach to the guitar and this current setup and I am pretty happy how everything is. I want a delay or verb for about 10 minutes but then I go back to playing and quickly forget about it.

It's good that you found your problem and I hope that TC has decent customer service to help you with your issue.

Greg

 

[Tuna141]

I've been leaning towards the minimalist approach lately too.

I've been playing my Mark IIC and Voc AC30 almost exclusively (w/no effects) lately. I had forgotten how good the IIC sounded. I hadn't even turned on my Triaxis/G-Major rack set-up for a couple of months and had discovered the previously problem when I plugged it in the other night. The G-Major issue is driving me even further to minimize the complexity of my rig. So, much so, that I'm contemplating selling the rack setup including the Triaxis and just go with a simple combo amp rig. And besides my rack is pretty heavy and I'm not getting any younger :lol:

 

[disassembled]

I just went with the TA to get into the Boogie realm (it was my first boogie preamp but I had the 20/20 for a few months prior) and have been very happy with my tone. The LD1 red really doesn't do much for me but the cleans and LD2 green and yellow really is where this pre shines IMO. I use the TA with a 20/20 amp in a 2 space rack and it drives my 212 to a live band level but doesn't get obscenely loud compared to a 100 watt EL or 6L6 based amp. The 20/20 gets to a certain point in volume (lets say 75% of the volume knob) but doesn't get ANY louder when you try to turn it up. This bothered me for a minute but then I realized how loud the amp was at that point and quickly came back to reality. The rack weighs about 30 Lbs all boxed up (minus the footcontroller) and is proctected during transit.

If I had tried a Mark IV before the TA i probably would have bought the Mark but since I live in Japan and will be here for the next couple of years it isn't worth paying to get a Mark amp shipped out here; especially when I don't even play with a band or gig at this point. If I play with someone I will probably take out my Epi Valve JR combo amp and OD pedal which really has a decent sound (modded of course). Even with the 20/20 and 212 cab I still need to turn the amp up to a level that will disturb the neighbors to get a good tone and that's probably going to be true with just about any amp that I would be interested in.

Now I am even looking to downsize my footcontroller as I don't need 10 footswitches and 2 expression pedals. I just bought a Parker Fly Classic to minimize my guitar necessities along with kill the need for a dedicated electric acoustic. The Fly gives me a humbucker guitar that can be fixed bridge, floating bridge, or down only bridge along with the piezo pickup for acoustic like tones. Before the Fly I was thinking Gibson LP or PRS along with and Ibanez, ESP, or Jackson with Floyd and some sort of cheapo acoustic/electric. I guess I will keep my Tele copy since it was $100 and is a great guitar to play (beautiful fat neck).

When I go home in a couple of years I am going to have a massive gear sale. The days of owning 12 guitars, 4 amp heads, 2 4X12 cabs, 6 space rack, huge foot controller, and massive wiring headache are over! I am thinking I will keep my current rack for a long while, get a DC-3 combo, get a mark IV head/combo, and maybe a british flavored amp to mix it up just a little.

Good luck with your tone search!

Greg