wtd: Extender boards for Cushman CE-50 service monitor

RoDnSuE · Post by **RoDnSuE** » Sat Dec 03, 2005 11:14 am

Hi all,
I'm looking to beg, borrow, or buy the left and right extender boards for a Cushman CE-50A-TG service monitor.
The one I have has an intermittant PLL unlock problem when tuning the 1 mhz digit upward past the 6-7 mhz position. It only happens when tuning upward, and only on the 1 mhz digit.
One other symptom I have noticed is, the scope shows a large sine wave when in generate before the unit has warmed up for 10-15 minutes. If the "frequency zero" control is adjusted way off of center, the sine wave disapears. As the unit warms up the sine wave slowly reduces in aplitude until gone. Other than the 1 mhz digit the unit works fine.
After reading the theory of operation it seems the basic PLL should be the culprit since it controls the 1 mhz digit and probably needs to be re-alligned.
If anyone has ran into this problem before I would appreciate any suggestions.

Thanks,
RoD

DJP126 · Post by **DJP126** » Sun Dec 04, 2005 4:10 pm

Hi RoD,

Just a guess at your scope problem (I've never worked on a CE50), but it sounds like a capacitor problem. As for an extender board, you might try EML in Franklin, TN. They used to deal with used test equipment but got out of that business. Maybe they have some.

RoDnSuE · Post by **RoDnSuE** » Tue Dec 06, 2005 10:08 am

Thanks for the tip. I first thought it was a power supply problem but after turning the zero control and having the sinewave disapear makes me think it's in the basic PLL. It still could be a cap but I'm going to need the extender boards to find out. I will give EML a call here in a bit.

Thanks again,
RoD