[Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread

[jsteiger]

Just got an LC25 together and it is always on bypass. when switched into "act" im getting no noise from the relays. The Switch is getting 4v dc

Look for backwards or misplaced diodes near the relays as well as backwards relays or the transistor.

 

[coldwar]

Look for backwards or misplaced diodes near the relays as well as backwards relays or the transistoevery

everything seems to be in order as far as that goes noticing now that the relays are a different part then what is on the bom they are marked tq2-24/atq204 not sure if that would make a difference

 

[jsteiger]

everything seems to be in order as far as that goes noticing now that the relays are a different part then what is on the bom they are marked tq2-24/atq204 not sure if that would make a difference

Indeed they would. For the LCs they must be 12V. I wonder if I gave my guy the wrong relays to pack...

 

[coldwar]

Indeed they would. For the LCs they must be 12V. I wonder if I gave my guy the wrong relays to pack...

Oh shoot! looks like that might be the case I will shoot you over an email.

 

[TeaBone]

Indeed they would. For the LCs they must be 12V. I wonder if I gave my guy the wrong relays to pack...

Same here! 2x LC25 and 2x LC40, all shipped with 24V relays. I'm glad you posted that! I built the first LC25 and was going crazy. Then I noticed the labels on the relays and wondered "how the hell are they supposed to get 24V?!" Now I know

 

[theblastedman]

Hey Jeff! Also having the same issue on finishing 2 builds of LC25 and LC40 just now, had ordered these about 2 months ago and lo and behold, 24v relays here. I'll reach out to you via email! Just posting here for posterity, shouldnt be a problem! Thanks in advance!

 

[hasanova]

Hi @jsteiger !

Finally made some time to start sorting and checking parts before building for a pair of LC25's and a pair of LC40's that I ordered about 2 months ago. And ... (I guess you know what I'm about to say...) lo and behold: there are a total of eight 24V relays here instead of 12V. I'll reach out to you via email!

Cheers!

 

[Tdub]

Indeed they would. For the LCs they must be 12V. I wonder if I gave my guy the wrong relays to pack...

I am in the same boat, 24V relays on both my LC25 and LC40. Is the best way to get in contact for replacement relays through the website email?

 

[jsteiger]

I am in the same boat, 24V relays on both my LC25 and LC40. Is the best way to get in contact for replacement relays through the website email?

Yes I saw your email. Sorry about the choke...

 

[MFG_TMM]

Hey all, I built two LC40s awhile ago and it looks like one is about 10dB quieter when I engage them. I switched the switch PCBs and it seems that the problem is with the main PCB. I saw a similar issue a couple of times on this thread, and it seems like it could be the headers, but I'm not seeing anything wrong with them, and I also didn't see anyone actually resolve this issue. Any help would be most appreciated!

 

[jsteiger]

Hey all, I built two LC40s awhile ago and it looks like one is about 10dB quieter when I engage them. I switched the switch PCBs and it seems that the problem is with the main PCB. I saw a similar issue a couple of times on this thread, and it seems like it could be the headers, but I'm not seeing anything wrong with them, and I also didn't see anyone actually resolve this issue. Any help would be most appreciated!

These boards have TP's (Test Points) on them so I would advise injecting a 1k sine wave and measuring ACV at all of the TP's on the good unit. Then check the bad unit and see where things change. That will help narrow it down.

 

[MFG_TMM]

These boards have TP's (Test Points) on them so I would advise injecting a 1k sine wave and measuring ACV at all of the TP's on the good unit. Then check the bad unit and see where things change. That will help narrow it down.

Thank you for responding so quickly Mr. Steiger!! The results on the good one (with a 1k sine wave fed from my DAW at -12dB, which is Logic's default):

TP 1: .953
TP 2: .952
TP 3: .952
TP 4: .952

Results on the bad one:

TP 1: .951
TP 2: .950
TP 3: .952
TP 4: .930

I don't know what all this means but it looks like TP 4 is the only real difference. Any insight on what I should check/what might be wrong? I've also attached a couple of pics in case that helps.

 

[jsteiger]

Thank you for responding so quickly Mr. Steiger!! The results on the good one (with a 1k sine wave fed from my DAW at -12dB, which is Logic's default):

TP 1: .953
TP 2: .952
TP 3: .952
TP 4: .952

Results on the bad one:

TP 1: .951
TP 2: .950
TP 3: .952
TP 4: .930

I don't know what all this means but it looks like TP 4 is the only real difference. Any insight on what I should check/what might be wrong? I've also attached a couple of pics in case that helps.

I would suggest desoldering all leads for the output transformer and checking the DCR for open or shorted windings.

 

[MFG_TMM]

I would suggest desoldering all leads for the output transformer and checking the DCR for open or shorted windings.

Thank you! I can give that a shot but I have no idea what I'd be looking for. Do I basically just peel off the copper tape and see if anything looks clearly messed up? If I find anything is there a fix for it, or would I have to replace? It looks like that is unfortunately the only transformer not available on the site right now.

 

[jsteiger]

Thank you! I can give that a shot but I have no idea what I'd be looking for. Do I basically just peel off the copper tape and see if anything looks clearly messed up? If I find anything is there a fix for it, or would I have to replace? It looks like that is unfortunately the only transformer not available on the site right now.

No don't peel away the copper! All you need is a DMM set to a low ohm setting. The readings should be around 10 ohms. Make sure no leads are touching each other and measure DCR. The only continuity should be between the start/finish of a winding and to no other leads. Use the datasheet on the site to know what colors are which.

 

[MFG_TMM]

No don't peel away the copper! All you need is a DMM set to a low ohm setting. The readings should be around 10 ohms. Make sure no leads are touching each other and measure DCR. The only continuity should be between the start/finish of a winding and to no other leads. Use the datasheet on the site to know what colors are which.

OK, thank you again! I think I figured it out. I measured the leads coming off the transformer and got roughly 10 ohms for these:

Red-black: ~10
White-yellow: ~10
Gray-pink: ~10
Violet-orange: ~10

Then I started measuring from black to all the others, red to all the others, etc., and got zeroes until white, where I got two that weren't zero:

White-gray: jumping around but roughly 1
White-pink: ~10

I haven't tested all combinations of yellow, gray, pink, purple, or orange, since I figured this was enough to know something was wrong. But I can if needed.

So what does this mean - I need a new transformer? I'd rather just do that than do many more hours of troubleshooting, if that's an option. Thanks as always!

 

[jsteiger]

OK, thank you again! I think I figured it out. I measured the leads coming off the transformer and got roughly 10 ohms for these:

Red-black: ~10
White-yellow: ~10
Gray-pink: ~10
Violet-orange: ~10

Then I started measuring from black to all the others, red to all the others, etc., and got zeroes until white, where I got two that weren't zero:

White-gray: jumping around but roughly 1
White-pink: ~10

I haven't tested all combinations of yellow, gray, pink, purple, or orange, since I figured this was enough to know something was wrong. But I can if needed.

So what does this mean - I need a new transformer? I'd rather just do that than do many more hours of troubleshooting, if that's an option. Thanks as always!

White to Pink should have no DCR. Something must be shorted internally.

Please send me an email thru the store. Reference this thread and gimme your order #. I'll get you squared away.

 

[MFG_TMM]

White to Pink should have no DCR. Something must be shorted internally.

Please send me an email thru the store. Reference this thread and gimme your order #. I'll get you squared away.

Will do, and thank you, I really appreciate it.

 

[Christian Rodriguez]

Hi all, question on the LC25 gyrator caps

I got a cap labeled 102k instead of 102j. Will that still work?

 

[jsteiger]

Hi all, question on the LC25 gyrator caps

I got a cap labeled 102k instead of 102j. Will that still work?

Yes. We probably could not get the J parts when we last ordered. J=5% tolerance, K=10%. Either way good to go.