[BUILD] CAPI FC526~500 Series~FET Limiter Kit~Official Support Thread

[Homestudio]

I'm using a Fluke 77 iv. Frequency is specifiedfrom 2Hz to 99.99 kHz. The sine wave is being generated from REW EQ Wizard program.
400Hz starting at .025vac in bypass
jumps between 16.80 to 17.10vac. The same results at 200Hz. No lights lit up at start of tests. Clip light is lit  in all tests when switched to act.

 

[jsteiger]

I'm using a Fluke 77 iv. Frequency is specifiedfrom 2Hz to 99.99 kHz. The sine wave is being generated from REW EQ Wizard program.
400Hz starting at .025vac in bypass
jumps between 16.80 to 17.10vac. The same results at 200Hz. No lights lit up at start of tests. Clip light is lit  in all tests when switched to act.

OK, in that situation, I would "guess" you have some resistors misplaced or problems with an opamp.

 

[Homestudio]

Okay, I've checked every resistor's color code and they look ok. I haven't replaced the DT05 yet. The gar 2520 came out of a working BT50. My thinking is that something burned on the DT05 when it got hot. Does this sound logical? BTW the diodes on the DT05. The leads from the black band go to the hole with the arrow correct? Thanks

 

[jsteiger]

Okay, I've checked every resistor's color code and they look ok. I haven't replaced the DT05 yet. The gar 2520 came out of a working BT50. My thinking is that something burned on the DT05 when it got hot. Does this sound logical? BTW the diodes on the DT05. The leads from the black band go to the hole with the arrow correct? Thanks

Yes the arrow points to the end with the black band.

I think you need to check the audio path test points and find out where this crazy gain is coming from. Just checking the output is not enough.

 

[Homestudio]

Wow, things didn't go well :-\

With 1000Hz sine @.024v and RV2 fully cw with input and output wide open.

Test points
1 = 0.0
2 = 0.0 to 0.1
3 = - 4.0
4 =  0.?
Smoked PR 2 on main pcb and PR 1 on the meter board. I'm guessing I souldn't have tested T4 at that point?

So I'll need to replace both.
I noticed the gar 2520 got warm before all went south.

 

[jsteiger]

If the PR resistors smoke, you have some build issues related to the opamps and or follower. I believe I have posted what all PR's service above so you can narrow down your mistake. Smoking one on the meter board would tell me an IC is in wrong or you have a direct short on it somewhere.

 

[Homestudio]

I went through the whole build replies and found.

PR3 goes to the +V pin of the DTO5 and nothing else

PR3 and PR4 are specially for the DTO5 so if they burned you have something wrong on that board

Couldn't  find any reference to PR2.  Also, I don't know what a follower is. Could you explain to a noob. Thanks

And BTW thanks for all the quick repies they're greatly appreciated.

 

[jsteiger]

Wow, things didn't go well :-\

With 1000Hz sine @.024v and RV2 fully cw with input and output wide open.

Test points
1 = 0.0
2 = 0.0 to 0.1
3 = - 4.0
4 =  0.?
Smoked PR 2 on main pcb and PR 1 on the meter board. I'm guessing I souldn't have tested T4 at that point?

So I'll need to replace both.
I noticed the gar 2520 got warm before all went south.

If you follow my test points guide, TP1-TP3 are for audio so ACV. TP4 is the audio feeding the sidechain rectifier so measuring ACV here should not have blown anything. Possibly a coincidental timing thing with the PR's smoking.

Here are all of the PR uses:
PR1=A1 +V and feed to meter board
PR2=A1 -V and feed to meter board
PR3=DTO5 +V
PR4=DTO5 -V
PR5=2520 -V
PR6=2520 +V
PR7= Discrete follower (Q1 &Q2) +V
PR8= Discrete follower (Q1 &Q2) -V

 

[Homestudio]

Well, I screwed the pooch on this. I replaced the smoked PRs and touched up the A1 solder.  But in attempting to remove the DT05 I missed up one of the wholes and its trace on the pcb. So I'm pretty sure it's toast. Would I be able to buy a  partial kit? It's now become a personal challenge to finish this build.

 

[labomatic]

Hi Jeff
Just finished the FC526, sound is perfect, but I have a problem with the metering.
all signal diodes lit.
TP9: -10,01
all values good on metering board.
but TP10 is -1,3v and RV1 & RV8 works, but always around - 1,2/-1,3v
Any clues???
Thanks
Dominique

 

[jsteiger]

Hi Jeff
Just finished the FC526, sound is perfect, but I have a problem with the metering.
all signal diodes lit.
TP9: -10,01
all values good on metering board.
but TP10 is -1,3v and RV1 & RV8 works, but always around - 1,2/-1,3v
Any clues???
Thanks
Dominique

Solder bridge or wrong placed resistors?

 

[jsteiger]

Well, I screwed the pooch on this. I replaced the smoked PRs and touched up the A1 solder.  But in attempting to remove the DT05 I missed up one of the wholes and its trace on the pcb. So I'm pretty sure it's toast. Would I be able to buy a  partial kit? It's now become a personal challenge to finish this build.

It depends on what you need. We aren't equipped to do "partial kits". Maybe send me an email and we'll see what can be done.

 

[labomatic]

Solder bridge or wrong placed resistors?

Everything is ok now. it was a problem in the motherboard ribbon cable connector. I had to remove it and solder a new ribbon directly on the board. When I will do my next order I will ask you 2 new connectors and a ribbon cable... Meter setup was really fast after. Sound of this little thing is just fantastic! Thanks Jeff

 

[Homestudio]

Email sent via contact us on your website. Thanks

 

[Homestudio]

Sent a follow up email via contact us on the website.

 

[jsteiger]

Sent a follow up email via contact us on the website.

Sorry I am not getting them. I am receiving others though. Please send to sales at capi-gear dot com.

 

[Homestudio]

Will do.

 

[Homestudio]

Jeff, I was wondering if the pcb is a multilayered design or is it one set of traces. I have conductivity from all pads to the next point in their trace. Maybe it's not toast after all?

 

[jsteiger]

Jeff, I was wondering if the pcb is a multilayered design or is it one set of traces. I have conductivity from all pads to the next point in their trace. Maybe it's not toast after all?

Its 2 layer only. Top and bottom copper. All pads are plated thru holes.

 

[Homestudio]

Hey Jeff, did you see the email I sent?
Thanks