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Old 24th Nov 2022, 11:08 pm   #263
regenfreak
Heptode
 
Join Date: Nov 2018
Location: London SW16, UK.
Posts: 655
Default Re: 6-gang FM stereo tuner heads

Quote:
Originally Posted by Radio Wrangler View Post
It's a fractional-N frequency synthesiser. I'm not sure whether it's one of the analogue-phase-interpolation ones. Unless you are very comfortable with these things, I wouldn't recommend trying to repair at home.

I had the job of redesigning the API frac-N synth in the 3325A around a new LSI ASIC a number of years ago and while it's doable, getting all the spurs in-spec is a major undertaking. It may be that the 30MHz PLL is a straight forward one for the heterodyne band. The synth itself runs 30-51MHz and is mixed down to giv 0-21MHz

David
Yes I would poke it with a stick. I had the pleasure of skipping through 316 pages of user manual and 166 pages of service manual today.

I saw an article that it described the 3324A as " a low cost" unit and the list price was $3500 around 1989-90. Threw it another $765 you would get a built-in OCXO frequency reference. Luckily the seller has been quick to offer the return without a fuss..not all the sellers are easy-going like that.

How many hobbyists injured their lower backs after moving HP spectrum analyzers at home? I was very shocked to find out how massive the 3324A is.
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