IFR 1200 help needed

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Darel
New User
Posts: 10
Joined: Tue Jan 03, 2017 7:19 pm

IFR 1200 help needed

Post by Darel »

Hello all,

Been a long time since I have been on this site. I recently acquired a virgin early 1200. ( 5000 range SN, 1.4 ver firmware ).

It has recently developed a problem. When you turn it on the display will come up "step 00 hz" and will be locked in that position. If I turn the scope off it seems to work normally ( but with no scope ). I checked ( and replaced ) the backup battery as well as checking the caps on that board. All of the P/S voltages are there but all seem just a tad low.

Any thoughts that might steer me in the right direction?

Thanks in advance,

Darrell
jry
Posts: 448
Joined: Fri Feb 06, 2004 3:14 pm

Re: IFR 1200 help needed

Post by jry »

re-cap the power supply.

I would replace the two large caps on the AC supply and all of the caps in the DC - DC converter

You can try to run off of DC and see if it does better but I would still re-cap regardless.

I would not replace the Tantalum ones ...they do fail but when they go it's usually a short and not an open.

The caps on theses older units need to be replaced proactively since when they fail they leak and oftern damage the PCB's
Darel
New User
Posts: 10
Joined: Tue Jan 03, 2017 7:19 pm

Re: IFR 1200 help needed

Post by Darel »

Jry,

Thanks! As it turns out you were right on the money. 2 bad caps inside the DC/DC converter took care of the problem. I went ahead and replaced the others as well.

Darrell
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