Looking for wattage meter lamps. Kenwood KA-8300

Pioneer!

Active Member
Picked up a Kenwood KA-8300 amp up the other day with a burnt out switch for $10, quickly had the switch jerry-rigged and it's working very well. I do need to locate lamps that backlight the output meters. The current bulbs are the following:

Stanley 8.0V 300mA mini lamp, has part number S86 on it with a rubber base, here is a picture
Here

Sorry, I didn't want to fill up your entire screen so I put a link to it.


If there is an equivalent available somewhere, I would greatly appreciate it if someone could point me in the right direction. If possible I can install some wedge lamp sockets that will fit in the holes and purchase matching-spec wedge lamps. I haven't had a ton of luck finding rubber base lamps with the same specs.
 
Pretty sure that the only choice here will be 8V 250mA wedge lamps. The difference in current is not an issue, but the wedge configuration is a small one (the lamps end up sitting a bit high in the silicone rubber support).
 
Sounds like the same arrangement found in the Sansui TU-517/717... one of the Sansui guys posted a DIY thread for replacing those OEM Stanley lamps by using the glass part w/leads that he removed from a bayonet lamp base (can use MES/E10 threaded globe lamps as well). Basics are to gently remove the metal base and then solder lead extensions on, then the whole thing drops into the silicone rubber fixture.

Doing it that way solves the height issue you get with wedge lamps but does take a bit more effort. Lamp values are available to support 8V/300mA in both bayonet and MES/E10 bases.

I don't know first-hand how the Kenwood version connects though, looks like maybe a longer harness is required. On the Sansui it's just a question of running the bare leads out thru the holes in the rubber support which then presses on over metal pins that also are the voltage source for the lamps. But, you could add longer wires and route them out of the rubber to adapt that solution for use on the Kenwood equipment.

I can dig up a link for that thread if anyone wants to look at it.


John
 
Pretty sure that the only choice here will be 8V 250mA wedge lamps. The difference in current is not an issue, but the wedge configuration is a small one (the lamps end up sitting a bit high in the silicone rubber support).

This is doable, if I can get the old lamps free of the housings and then cut the leads and solder straight onto the wedge lamps
 
Sounds like the same arrangement found in the Sansui TU-517/717... one of the Sansui guys posted a DIY thread for replacing those OEM Stanley lamps by using the glass part w/leads that he removed from a bayonet lamp base (can use MES/E10 threaded globe lamps as well). Basics are to gently remove the metal base and then solder lead extensions on, then the whole thing drops into the silicone rubber fixture.

Doing it that way solves the height issue you get with wedge lamps but does take a bit more effort. Lamp values are available to support 8V/300mA in both bayonet and MES/E10 bases.

I don't know first-hand how the Kenwood version connects though, looks like maybe a longer harness is required. On the Sansui it's just a question of running the bare leads out thru the holes in the rubber support which then presses on over metal pins that also are the voltage source for the lamps. But, you could add longer wires and route them out of the rubber to adapt that solution for use on the Kenwood equipment.

I can dig up a link for that thread if anyone wants to look at it.


John

I'd be interested in seeing a case where someone has done this before, so I can make sure I have the same idea. Would like the link :yes:
 
This thread shows the wedge lamp method, although I *think* you have to actually solder to flying leads on the Kenwood, but that's just from looking at a picture online (from dgwojo's site: http://www.dgwojo.com/web_images/8v_wedge_lamps_01.jpg).

http://www.audiokarma.org/forums/showthread.php?t=429288

This one shows the method I prefer (posted by skippy124), using the globe part w/leads removed from either a bayonet lamp or MES/E10 threaded lamp:

http://www.audiokarma.org/forums/showthread.php?t=369708


John
 
This thread shows the wedge lamp method, although I *think* you have to actually solder to flying leads on the Kenwood, but that's just from looking at a picture online (from dgwojo's site: http://www.dgwojo.com/web_images/8v_wedge_lamps_01.jpg).

http://www.audiokarma.org/forums/showthread.php?t=429288

This one shows the method I prefer (posted by skippy124), using the globe part w/leads removed from either a bayonet lamp or MES/E10 threaded lamp:

http://www.audiokarma.org/forums/showthread.php?t=369708


John

Those bases seem a bit different, but it's pretty much the same principle I reckon. Sourcing those bulbs that skippy used would be great because those are the exact ones i need
 
For sure. I did check, and you can get 8V/300mA in both base styles, bayonet or threaded mini-screw. They should come apart the same way too, and both types looked fairly inexpensive - buck something apiece at the most.


John
 
When I redid my lamps, I cut out the bottom of the grommets and used standard screw-type lamps. I don't remember whether I soldered in some new wires or used the old ones.
After half a year, they are broken again, looks like the power supply for the lamps is playing up.
 
When I redid my lamps, I cut out the bottom of the grommets and used standard screw-type lamps. I don't remember whether I soldered in some new wires or used the old ones.
After half a year, they are broken again, looks like the power supply for the lamps is playing up.

Did you unsolder the screw base from the bulbs or did you just solder to the outside of the screw base? The latter sounds much easier and I can snag bulbs at this spec fairly easily at one of the electronics shops around here. I've honestly been too busy to experiment with it as of late. Does anyone know the voltage of the LED power indicator off-hand or can I find it in the service manual? Mine doesn't work of course. I THINK the secondary model number in the manual references a Panasonic GD4207RD red diode if that helps anyone. Most online retailers have them tagged as NLA :/

Edit: I cross-referenced this old Kenwood thread and determined that the LED "grab bag" at Radio Shack will hold what I need to replace it. What is weird is the pilot diode is supposed to act as a protection circuit, but my amp works fine without it in the circuit at all, maybe the 8300 behaves differently? Nevertheless, I SHOULD be able to get that tonight, and bulbs if I can find them.
http://www.audiokarma.org/forums/archive/index.php/t-282727.html Also tested to see if I was getting voltage from the LED leads that are on the power supply board and that shows a steady 43.7 volts. My eyes are no good and I cannot read the schematic to see if this is even remotely correct. Looking at the power supply board in the schematic I think I can see a 51(46v) circuit and several 50v circuits, not sure which one goes to the diode though, my eyes are fighting me.

If someone could verify if this voltage is nominal, that would be awesome.
 
Last edited:
I just soldered on the screw part of the lamp. It's not perfect and a lot of fiddle but it worked for a few months. Removing the screw part and using the grommets normally should work better. I did so far not have time to figure out what happened and why the lamps went bad. I might replace them with 12v lamps (this is the case in my other 8300). They don't look as white as 8V, but I think the power supply is providing more than 8V to the lamps.
 
I am taking this to my tech over the holidays and am going to have him go over the power supply board and see if he can solve the mystery as to why I have no voltage from the lamp circuit. Might just get him to replace the lamps too if it doesn't set me back too much. I suspect he's gonna change the resistors and the 50v cap on the power supply board at the very least. That cap MAY be leaking but it could also be adhesive, hard to tell.
 
Well it turns out the guy I know doesn't do repairs anymore. Seems a bit silly but okay whatever floats his boat.

So now I have the burden of finding someone very affordable or attempting the repairs myself. Should be getting a digital soldering station for Christmas. I will probably make a new thread later on when I can share my test results with you.
 
Back
Top Bottom