Kenwood L series.

HI all AKer's, I got a pair L-07M II brand new never use, test and sound good. Follow EchoWars's advice I will replace all black caps. My question is do I need to replace all other aluminium electrolytic capacitors since they are 40 years old?
Thanks
We discuss that all the time. Some do, some don't, some test and replace the bad ones, some test the unit and if it meets specs they move on, but those guys have the test equipment needed to verify performance of the unit. It really is your call. There are not a lot of caps in a power amp. Receivers have about 100 but a single channel amp, I think the L-09M has about 15 or so. Not to hard to get a handle on that project, if you can get to the caps.
 
HI all AKer's, I got a pair L-07M II brand new never use, test and sound good. Follow EchoWars's advice I will replace all black caps. My question is do I need to replace all other aluminium electrolytic capacitors since they are 40 years old?
Thanks
Yes - if you're refurbishing a piece replace all electrolytic capacitors. I've learned from hard experience that 40 year old caps may test good today but they can go out of spec anytime and take out unobtainium parts.
 
both actually. I have the 07 and the yes it has the unobtanium parts in them also.
Yea, gonna have to disagree, L07M parts are not unobtainable, power transistors NOS & subs for all others smaller transistors available, did both my L07s 6 months ago. Caps available everywhere. I don't know about the L07MII different power transistors I hear.
 
Look at the power transistors - they ARE unobtanium because they switch at a high frequency. If you replace them, it will not be the same. And yes, the L-07M is a true switching amp. This is information from the gent who rebuilt mine and he has several patents on power transistors.
 
Won't be the same? Don't know how you figure that, there are 3 adjustment pots for supply voltage, bias current, & center voltage. Both mine worked when I bought them off eBay, had a couple mismatched transistors, replace with correct ones, 2SC1116a & 2SA747a. Completely recapped both. Sound just great. How does your "gent" have a patent on Sanken or Toshiba power transistors?? Sorry but mine both sound perfect. Don't know where you get your info, plus I also have spare power transistors on hand.
 
Here is a pair of L-05M's tucked under the TT. I cleaned up and installed all new caps, a few resisters and some hardware on the back plate. The big filters had to be custom fitted due to the difference in modern sizes. I broke a rare thermistor, but thankfully I had a spare sitting in an old amp. WHEW! When my Sansui Alpha AU707 Extra died from unobtainium, these guys took the place of power. As much as I adored the Sansui, I am not disappointed at all. The front end is my stalwart Melos GK 1+1 tube preamp. As Echo Wars said somewhere, they are very easy to work on. They have as much power as I will ever expect I'll need, so I hold no envy for the 7's or greater.L-05M.jpg
 
Looking for a Protection/Relay board for an L07M I bought for parts, it's complete except for that, the X00-1890-10 slide in board with the 2 large 470uf 100v caps. Got it for $34 off eBay.
 
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