Spectra Caps

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GlennD
Posts: 482
Joined: Tue Jun 15, 2004 8:00 am

Spectra Caps

Post by GlennD »

I have been going through a bunch of brand new Spectras from 1995 originally intended for a Command vehicle that never happened. All of the radios look pristine inside with no signs of cap leakage.

In about half of the removed caps there is beginning corrosion and one 47MFD on the rf board was already eating traces. IN MY OPINION ALL SPECTRA ELECTROLITIC CAPS MUST BE REPLACED! Visual inspection is not good enough.
Will
Posts: 6823
Joined: Tue Sep 04, 2001 4:00 pm

Re: Spectra Caps

Post by Will »

Much agreed.

We do not use electolytics for replacement. Only Mil spec sealed surface mount capacitors.
kc7gr
Posts: 1027
Joined: Wed Mar 13, 2002 4:00 pm
What radios do you own?: Motorola, Icom, Sunair (HF).

Re: Spectra Caps

Post by kc7gr »

Would those be the mil-spec tantalums, Will?

In any case... I have found that high-quality electrolytics (the Panasonic HD series) hold up very well indeed. They're rated for 5,000 hour life at 105 degrees C, and they are almost the exact same form factor as the original parts.

I will add that If your radio is operating in temperatures like that, you've got other problems! :o

Happy tweaking.
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Bruce Lane, KC7GR
"Raf tras spintern. Raf tras spoit."
GlennD
Posts: 482
Joined: Tue Jun 15, 2004 8:00 am

Re: Spectra Caps

Post by GlennD »

In our case we use electrolitic caps purchased from Mauser. I do not know the part numbers since the parts guy stocks them under the Motorola numbers.

As a city long lasting is not a consideration. They only have to last until Jan 1, 2013 since they are not narrowband radios.
videonerd
Posts: 259
Joined: Thu Aug 19, 2004 9:48 pm
What radios do you own?: Little Tikes walkie-talkie

Re: Spectra Caps

Post by videonerd »

Does anyone have instructions or tips on how to solder those smt caps?
I'm ok with a soldering iron, but not with the SMT caps that I ordered!

-Phil
kc7gr
Posts: 1027
Joined: Wed Mar 13, 2002 4:00 pm
What radios do you own?: Motorola, Icom, Sunair (HF).

Re: Spectra Caps

Post by kc7gr »

There is a bit of an art to it, admittedly. Took me a couple of tries to get it right, and no two people will favor the exact same method.

What I do, after cleaning the board of the old caps and electrolyte residue, is put the new cap into place with a fine-point probe, then hold it down with a middle finger and use a needle-point tip on my soldering station to tack down one leg. I can then let go, and do the other leg without worrying about the cap getting nudged out of place.

My favored soldering station for the task is a Weller/Cooper EC3001 series. The pencil is small and lightweight, and there are a variety of tips for it that, if used under a magnifier, could probably solder leads on 100-pin QFP chips without much hassle.

The most important things are patience, the right tools, a well-lit work area, and a high degree of soldering skill.

Happy tweaking.
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Bruce Lane, KC7GR
"Raf tras spintern. Raf tras spoit."
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mancow
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Re: Spectra Caps

Post by mancow »

Would any of you guys have a list of what caps need to be replaced in a high power Vhf drawer? We have a few at work that need worked on and it would be great to have a list stating that you need x number of this type and x number of that type for each drawer so I could put in an order somewhere.
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kcbooboo
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Re: Spectra Caps

Post by kcbooboo »

Back in June I ordered caps to do four dash-mount radios, plus have a few extra. Each radio uses 11 or 12 caps. These are MOUSER part numbers.

5 647-UWT1C470MCL1B Nichicon SMD Aluminum 47 @ 16v

20 647-UWT1H100MCL1B Nichicon SMD Aluminum 10 @ 50v

30 647-UWT1C100MCL1B Nichicon SMD Aluminum 10 @ 16v

Perhaps you'll notice my AVATAR somewhere near this message. I won't come right out and say it, but there might be a rather detailed article about Spectra Caps on that web site. Of course, no one on BatLabs will read it because it comes from that "other" site... the one where they CAN say "radio soyviss roftware" and not incur the wrath of every administrator or moderator.

Bob M.
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