Film-Tech Forum ARCHIVE: cp55 stays in bypass

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Posted by Christos Mitsakis (Member # 143) on 03-31-2008, 11:38 AM:

On power on, cp55 remains in bypass. Haven't seen the unit. Fuse ok. There is a spare cat249 and on swaping the problem remains. I suspect the bypass relays. From your dealing with similar situation what is the most usual culprit: Relays, cat249 or cat 250?

Christos

Posted by Steve Guttag (Member # 268) on 03-31-2008, 12:48 PM:

Are the three power rails lit?

Try removing the cards, one at a time, and see if after removing one of them, it doesn't come out of bypass. Then reinsert all but the last card you removed before the unit came out of bypass. If that fixes the problem, then that card is pulling one of the rails down.

Steve

Posted by Louis Bornwasser (Member # 3063) on 03-31-2008, 01:52 PM:

Adding to Steve's post:

Control for those relays is in the 249.. Try swapping.

I do not suspect relays. Years ago, they used bad relays but surely all of these have long ago passed into history. They would click but did not pass audio. I would check this last. Louis

Posted by Steve Guttag (Member # 268) on 03-31-2008, 02:21 PM:

Louis, He said he tried swapping the Cat 249 so hence I moved on to seeing if one of the over-current protects came on line.

Steve

Posted by Christos Mitsakis (Member # 143) on 03-31-2008, 02:30 PM:

Thanks Steve and Louis. I'll be there to check the day after tomorrow, returning on thursday. In the meantime revisiting the diagrams in the manual, I ran upon the ac sense control in cat249: If no ac then go to bupass!, or the 24v rail to the relays. For the moment everything is just a speculation, I'll post upon my return.

C.

Posted by Christos Mitsakis (Member # 143) on 04-05-2008, 03:30 AM:

Simple as a blown main fuse, yet confusing.
The fuse by eye inspection didn't seem blown, that tricked operator when I asked to check the fuse.
Indeed it was my second priority when I found no dc on the relays.
I haven't been aware for the fuse value change during the years.
Cat250 and "newer" manual requests a 250mA slow blow fuse (remember we are in a 220V mains), where older manuals specified a 300mA fuse.
I suspected some shortcircuit at cat249. But no. Having cat250 with no load the 250mA fuse still blows upon closing the main switch (or by returning to Normal from Bypass). I tried the older value of 300mA fuse and everything is perfect.
The transient during power on is high enough that kills a T250mA fuse but not enough for a 300mA.
Athough the cp works fine now, I am going to exchange cat250 and take the faulty for further inspection. Now I am leaning towards the transient supressor on the voltage selector, or the line filter. Any Ideas?

Christos.

[ 04-05-2008, 01:28 PM: Message edited by: Christos Mitsakis ]

Posted by Marco Giustini (Member # 4544) on 03-06-2009, 08:55 PM:

Are CP65 Bypass relays 24V type?

Thanks
Marco

Posted by Steve Guttag (Member # 268) on 03-07-2009, 09:17 AM:

Yes.

Steve

Posted by Marco Giustini (Member # 4544) on 03-07-2009, 03:44 PM:

Thank you Steve!