Tektronix 7633 cannot accept 7L13

Mar 18, 2008 2 Replies
M

Hi,



I've tried to fit a 7L13 into a 7633, and it won't go in completely, the last



2 mm get stuck. Other modules go in OK, the 7L13 is somewhat longer at the left side. The problem turns out to be caused by metal cover plates over the two PCBs that are between the vertical module connectors at the back of the bottom space where you put in the modules. If I remove the cover plates, it is OK. The exploded drawing in the service manual doesn't show these plates. The PCBs are labeled there A4 (left PCB, trigger selector if I understand correctly), and A4 (vertical interface).

Question: are these cover plates original? Can they be removed without bad effects? The 7633 serial number is 704234 . I have seen a 7613 without these covers.



Thanks, Mat Nieuwenhoven


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J

"Mat Nieuwenhoven" wrote in news: snipped-for-privacy@news.chello. nl:

I don't recall seeing cover plates on any 7633 interface boards while I worked at TEK(US-Orlando). I'm fairly sure you can remove them without problem.

I believe you should check your LV PS electrolytics,and IIRC,there was a fan mod for 7600 scopes using 7L spec analyzer PIs. The SA plug-ins draw a lot more current and make a lot more heat.

You also may have to change a current limit resistor on the LV regulator PCB. IIRC,you bridge one of the current-limit resistors with another to raise it's current limit point.

Unfortunately,I can't recall which one or the values.Sorry about that. The service manual schematic may show the change. and it may already have been done to your scope.

Jim Yanik jyanik at kua.net
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M

Thank you for your reply. I've removed them. The scope came originally from a professional UHF/SHF equipment designer, I've mailed him if he had added them (and why).

I don't think it is a problem. I measured power consumption with a 7B53A /

7A22 / 7A26 combination at 146W (230V) . With the 7L13 it is actually slighty less, 145 - 141 W . But I'll check the manual anyway. The backplate of the scope says 'max 170 W' .

Thanks again, Mat Nieuwenhoven

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