Author Topic: 651 section slot 22 cap >>SOLVED<<  (Read 1731 times)

oyanliz

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651 section slot 22 cap >>SOLVED<<
« on: October 17, 2017, 12:37:56 PM »
Hi,

I do not know wht is this cap for. It is a 1,5uF 50v electrolitic capacitor wich I have replaced by 1.5uF 63v film capacitor. After replacement, I have some issues , but I am not sure if it is because of thet, I also have changed other things so...

I would apreciate if someone could tell me what is this cap for.

Thanks in advance.

Best regards.

Oihan
« Last Edit: October 20, 2017, 01:04:39 PM by oyanliz »

Matt Sartori

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Re: 651 section slot 22 cap >help<
« Reply #1 on: October 18, 2017, 10:45:22 AM »
Hi,

I do not know wht is this cap for. It is a 1,5uF 50v electrolitic capacitor wich I have replaced by 1.5uF 63v film capacitor. After replacement, I have some issues , but I am not sure if it is because of thet, I also have changed other things so...

I would apreciate if someone could tell me what is this cap for.

Thanks in advance.

Best regards.

Oihan

That is a bit vague, what other issues are you having?

Matt Sartori.

oyanliz

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Re: 651 section slot 22 cap >help<
« Reply #2 on: October 18, 2017, 11:08:02 AM »
You are right, sorry about that.

- Monitor pot is doing more noise (pops) when moving (betwen rotary steps or positions)
- Mini switch is working all the time, lamp is on all the time (when main monitor is using, switching "Mini" on, signal is cutted on main monitor. But there is signal all the time on "Mini LS" outputs of the patchbay and the Mini switch light is on all the time)
- Dim pot and Mni LS pot seem that they sound lower

I am getting crazy with the external to monitor and monitor section in general. I have been able to put everything working except external monitoring selectors, but now everything is getting worse again.

I want to start checking everything again, but I do not know what this cap is for, so that is the reason why I am asking about it.

Thanks for replying, Matt.

Regards.

Oihan

waltzingbear

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Re: 651 section slot 22 cap >help<
« Reply #3 on: October 18, 2017, 05:56:02 PM »
you have switching problems in your monitor path. Could be several things, but you need to get in and follow the signal (scope) thru the stages you have mentioned and see where it fails or changes in the wrong way.

The popping may be part of the problem (DC in the monitor path) or it could be just dirt in the pot, hard to tell from here.

to identify the function of the cap, you probably will need to identify the pins it connects to and on which card to "bring" it into the schematic. Ring it out. (that means use a DMM in resistance mode and set it for beep on short)

Cheers
Alan
Alan Garren
Waltzing Bear Audio

oyanliz

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Re: 651 section slot 22 cap >SOLVED<
« Reply #4 on: October 19, 2017, 12:55:45 PM »
Hi,

I do not know what is exactly this cap for. It is installed between 0V and a light brown wire on the socket of the CF82E21 card. I thought it was something standard in the 651 board but I am not able to find any info in the documentation (I do not have the original manual, I only have the manuals and schematics downloaded and bought on this forum).

Regarding to the problems on the monitor section:

- I found a TL074 op amp wit a broken leg on card CF82E24
- I found a 4023 IC plugged upside down on card CF82E22
- I will change the main monitor pot by one used but cleaned internally

Mini LS, Dim, Monitor cut... everything is working fine again. I hope the main monitor pot issue will be caused by dirt.

The external to monitor section still does not work. I am talking about it in another post of mine.

Thanks for helping!!

Regards

Oihan