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Author Topic: Kenwood SP-820  (Read 1569 times)
AB1YY
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Posts: 5




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« on: February 27, 2017, 05:03:02 AM »

I recently purchased a Kenwood SP-820 external speaker at a hamfest. I was told it was in working condition. However, when I got it home and opened it up, I found that the filter board had been disconnected from the rest of the unit; the wires having been cut. If the filter section had failed for some reason, I can't understand why the wires  were cut. I would think the front panel switches could have just been left in the "off" position. Has anyone had any experience with this model of external speaker? Thanks for your help!
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N8YX
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Posts: 918




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« Reply #1 on: February 27, 2017, 09:57:32 AM »

I have three of them.

The front panel switches get dirty, become intermittent...and someone might have bypassed the whole shebang instead of addressing the switch problem.

Is the board still present in the unit?
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K8AXW
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Posts: 6163




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« Reply #2 on: February 27, 2017, 11:42:50 AM »

The switches on that speakers are without a doubt the worst switches I've ever encountered in 60 years of ham radio!  I can clean them one day and a few days later they are intermittent again.

I can understand the frustration of the previous owner and one of the things I've always planned to do is bypass everything in the speaker box and install my own filters! 

Rotsa Ruck in getting that thing operational!
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WB3GNJ
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« Reply #3 on: July 17, 2017, 07:34:46 AM »

i also picked up a hamfest sp-820, great price and guaranteed to work.
dead so troubleshooting showed all ok, so hosed down the pushbuttons with
my CRC pf precision cleaner electrical grade and after two cleanings all ok now.
lot of screws so hope i dont have to do it often, love the filters.
jim kw3u
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KB7TT
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Posts: 13




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« Reply #4 on: July 17, 2017, 08:55:30 AM »

I have an SP820 that works fine with no intermittent switches.  I think maybe the life of the switches is more due to the environment the speaker lived in for the past 30 years.  Lots of ham shacks are in garages and other semi-hostile environments.   Fortunately for me mine has been in the house in a dry climate in CA and Oregon.  Cleaning the switches is a good thing.  The schematic for the speaker is available in the Kenwood SP820 manual on the web.  I think it is also in the back of the 820 service manual also available for download.

FYI

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K8AXW
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« Reply #5 on: July 17, 2017, 10:10:05 AM »

UPDATE on previous post:   I am now deaf as a fence post without headphones and an amplifier so the speaker is now just a "matching box" to the rest of the Kenwood gear.

However, let it be noted my speaker is inside 24/7, dry shack and non-smoking area.  I continue to stand by my previous comment about installing a better filter and removing the existing filter. 

The original filters are archaic and have no place in modern ham radio.
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N8YX
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« Reply #6 on: July 17, 2017, 10:25:00 AM »

...The original filters are archaic and have no place in modern ham radio.
Pair the speaker with its matching R-820 and the filters come in quite handily for SWLing.

I use mine in this fashion all the time.
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K8AXW
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Posts: 6163




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« Reply #7 on: July 18, 2017, 08:38:20 PM »

YX:  I'm by no means saying they "don't work" but saying they design is archaic and perform pretty bad.  The switches on mine gave me constant problems when I was using it.

I still plan to simply bypass the existing filters and install a variable filter/amplifier circuit.  Such circuits are usually simple and work well.  Of course if your hearing is anything close to normal, the amp wouldn't be necessary.

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