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Re: New here with a 2465 to clean up

 

Thanks Cslim.? I didnt get much time to work on it today.? But did do some visual inspection.? Many of the caps apear similar in color (copper/gold color) and manufacture.? I believe they are original.? C1101 looks to be?original and is labeled as 100 ufd.? C1102 appears to have been changed (kelly green color)?but is also labeled 100 ufd.? C1116 (original) has been leaking inside its vinyl sleeve.?? C1113 (original) is?bulging at the bottom and will be leaking soon.? C1132 (black) looks to have been replaced at some time.? Also, it looks like diode CR1115 has been replaced at some time.? And diodes CR1103 through CR1106 appear to run hot (the board is slightly discolored under/near them).? Measuring with a miltimeter shows the diodes still rectify and have similar "resistance" in the conducting direction.? I was surprised to see C1021 and C1022 look?almost like new.? I cant tell if they have been replaced but they are labeled Sprague and I think they sold the capacitor business to Vishay some ten years ago.
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So, I definitely need to replace the electrolytics?in the LVPS which is no surprise.? I will measure their values when I pull them just to see how bad they got.??But that task will have to wait till?I get some?uninterrupted time.? Hopefully later this week.?
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Meantime I plan to look at the fan motor assembly to see why it doesnt run.? I am confused how it works though.? Maybe someone can help me.? I understand the voltage control transistor (Q1698) and the coil dirve transistors (U1690) but I dont understand what drives the base junctions of U1690.? It looks to me there are burshes or contacts of some kind that connect to motor terminals 2, 4, 6, and 8.? Or are those Hall effect jucntions?? My confusion is "what drives the base junctions of U1690 to commutate the coil drive as the armature turns?
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Again, thanks to all who have helped me on this project.? I hope you are having fun.? I am.
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Mac

From: Chin Siang Lim To: "TekScopes@..."
Sent: Monday, March 11, 2013 7:16 PM
Subject: Re: [TekScopes] New here with a 2465 to clean up
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Not able to access this spreadsheet link using my iPad.
There is one capacitor, c1101, which is just above the rows of diodes and beside the transformer, it is a 100uf cap. This must be a 100 uf cap to give the -8volts. Do not change its value.?

CslimOn Tuesday, March 12, 2013, machineguy59 wrote:

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Of course. I should have done that in the first place. Here is the link to a spread sheet sowning parts to re-cap the OVPS of a 2465B:
http://f1.grp.yahoofs.com/v1/bF4-UQa4lyGEp6utufRdlNhXEK6fip8OC-bMdb1wtFsYserp-dPNaydifJoV59DLIdkwq4bZ_ErE-tFr1oF3i16dPrSCdVuiihw/2465LVPS_ReCap.xls

This is a spread sheet done by Random Walk and is a very complete listing including links to Mouser parts on the web. I verified the list against the service manual for a 2465, identified a few extra I wanted and ordered parts.

--- In TekScopes@..., Dave C wrote:
>
> Can you please give the link?
>
> Thanks,
> Dave
>
>
> The spead sheet posted at Tekarc was very helpful and still relevant.
> ...Mac
>
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