TU417/517/717 Lamp Replacement OEM style

skippy124

Super Member
Hi,

Having recently aquired 4 TU417's and hardly a lamp still working, I thought I would do a bit of research to see if there was a suitable replacement bulb that didn't require modification to the rubber bases (the wedge base replacement option, which also makes it hard to use the original blue tint lamp shrouds), and maintained an OEM look.

This is my solution -

A bit if fiddling, and here is a replacement bulb

TU417newlampbare.jpg


And fitted to the rubber holder, no mods needed

TU417newlampinassembly.jpg


And fitted to the Tuner - the bulb diameter is slightly larger (11mm compared to the originals at 10mm), so the shrouds need a slight squeeze to get them on, but is is fairly easy to get them into place over the new bulbs.

TU417newlampinplace_2.jpg


Lights on

TU417newlampinplaceon.jpg


And a couple of front panel shots

TU417front2.jpg


TU417front1.jpg


The bulb spec is 7.5V 220ma, 1000 hour and 1 MSCP output. The measured voltage in situ is 7.6VAC, so it is pretty close to the voltage spec of the lamp. The actual measured output of these alternative lamps is around 0.8- 0.9 MSCP

As part of the research I tried the 8V 250ma globes from vintage electronics, but found them to be a tad dim at arounbd 0.5 MSCP output. I also tried an 8V 300ma wedge globe from a local supplier, and it was around 3 MSCP (6 times brighter than the 250ma one). The 417 I have changed the globes in did not have one working original, so I could't measure the output of an original lamp for comparison purposes, but hopefully one of the other 417's I have will have a working lamp.

It helps if you have one of these when doing this sort of work

Lumasphere_sm.jpg


A Lumasphere for measuring the light output from small light sources (it measures in Lumens - divide by 12.57 to get MSCP)

Now.... where did the bulbs come from......

They are "removed" from a standard G 3 1/2 Lamp (CEC part number 51, and they are also available from CML I think under the same generic number). The "removal" takes a couple of minutes, and then I tack soldered some 30awg wire wrap wire on to the ends of the existing wires to extend them.

I have an enquiry in with CEC to see if they can supply a quantity of the bare bulbs with longer wires, hope to have some more info next week. Also exploring the possibility of getting 8V 300ma bare bulbs made to give a bit more light output. It may also be possible to use 8V 300ma B9a style lamps (think I have found a source of these), these would sit similar in height to the wedge base as they have an elongated bulb. I am going to try this for comparison purposes if the source comes good.

Hope this is of interest to those contemplating lamp replacements in these Tuners.

Cheers

John
 
Awesome research John!!

Please keep us apprised of your further findings. Many of us will benefit from your efforts, and if you can lay in stock of of bulb made special for this purpose, I and others I'm sure would be happy to buy them from you.

Scott T.
 
Wow, is that a Klingon disruptor?

Nice work though. You really do need that kind of equipment to measure the actual light output of substitute bulbs. I've tried many different fuse lamps looking for suitable replacements and haven't found any that are as good as the originals.

For the round bulbs in the G series and others, I've been using 8v 250ma wedge bulbs. They seem to work pretty well.

Where do you get your bulbs?

- Pete
 
I'd love to have a source for these too, I've been using wedge base bulbs and modifying the circuit board....
 
Brilliant solution, thanks for sharing it with us all!

Would have never thought to extract just the bulb parts from a G3.5 lamp, and I use those regularly so they've been under my nose the whole time.

John

P.S. If you do a search for #51 miniature lamp, you'll be tripping over a plethora of sources: bulbtown.com, lightbulbsdirect.com, Grainger, atlantalightbulbs.com, and a few choices here:

http://www.newark.com/jsp/search/br...onLocale=en_US&catalogId=&prevNValues=1003882

Looks like the E10 screw lamps would work too, assuming the bulb comes out the same way.
 
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I notice some brands can be removed from the base easier than others, 8v lamps would be nice with a life span of 10,000 hours, pretty cool, Dave. :thmbsp:
 
Thanks everyone...great info and documentation.

I experimented with a Bi-Pin 8v 80mA bulb which was fairly simple to construct, but DID NOT give off enough light. However I thought it might give someone else a brainstorm on a different approach. The pins are thick enough that they hold well being inserted from the top. See Photos.
 

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Ya ... I know ... old thread ... so shoot me already!! <G>

Went in another direction with my QRX 9001. That has five of these lil rascals, two behind the signal meters, and three to light the front panel. I tried the bayonet type bulbs shown in the bottom right but those didn't allow much clearance behind the meters and were definitely too tall for the dial lamps.

meter-lamps-(3).jpg


Final solution was the LEDs ... those are commonly available for automotive interior lamps.

led-wedgie.jpg


Warm white, high intensity. The bayonet base just pulls right off once you pry the wires away from the sides.

led-lighting.jpg


Rated 12v, but that usually means they'll fire at anywhere from 7v - 16v. These work well as a simple swap into the original Sansui holders, and no discernable flicker. 8v feed from the chassis, but at that level, the high intensity bulbs are just about perfect. The light from the three bulbs to the left of the faceplate (taped over in the top pic to test) bounces around inside the glass to light the entire dial area, and these give a nice even wash all the way across. Bonus - the original blue shields clip right over the LED bulbs and the color is extremely close to original if not spot on. The Sansui puts out AC for the bulb circuit, but no discernible flicker that you might sometimes get from a DC bulb, so no other mods required ... just plug em in.

PS ... lower left, you can see I trimmed one of the Sansui bulb holders for a bit more clearance, and ended up doing the same with the rest. I also added a spot of hot glue inside each to seat the LEDs better.
 
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Just to clarify, the lamps you mention on the lower right are T 3-1/4 wedge base, not bayonet. The ones skippy used in the first post are bayonet (metal base with small post sticking out on either side, installs via push in & turn), big difference in the overall height of the lamp. Same would be true of the glass removed from an E10 G3.5 lamp (metal threaded base), though I didn't provide a picture.


John
 
@sKiZo ~ could you give us a little more detail on the LEDs you used? Did you buy them in bayonet form? (like this) and remove the LEDs, or did you find a source of just the LEDs themselves? Have searched but no joy finding the latter.
 
Wow ... the thread lives on. <G>

For whatever reason, this pic disappeared in my original post.

led-wedgie.jpg


You can see these pop right off the base - just bend the wires straight and slide them out. Here's the exact bulbs I got:

https://www.amazon.com/gp/product/B00DZXMURU/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

As mentioned earlier, these gave me almost exactly the same light output and color temp of the original incandescent globes in my Sansui. No issues a year later.

PS ... I stand corrected ... these are technically "wedge" type bases, not bayonet.
 
I like those with the removable wedge base, I'm keeping few dozen 6.3 - 8v ac/dc around for those rubber base requests.
 
I like those with the removable wedge base, I'm keeping few dozen 6.3 - 8v ac/dc around for those rubber base requests.

Just keep in mind the ones I pic'd ARE 12VDC. The 7VAC supplied by a typical Sansui is technically outside the recommended operating range, but ... close enough for an ex-government worker. <G>

As stated, I really like the output, they DO fit the standard globe bulb color shields, and they've been doing daily duty for a year now with no issues. Simple enough swap into the stock bulb holders too ... just thread the wires in, poke them through the matching hole, and they slide right on the power pins on the light board.

PS ... the LED "flicker" probably wouldn't be an issue for most folk, making the rectifier optional. I figured, long as I was in there ...

Oh. And I DID try the incandescent bayonets, but the bulbs ended up way to close to the backs of the meters. Pretty bright hot spot, and I could see some heat issues in my future.

meter-lamps-(4).jpg


I still get a hot spot with the LEDs, but it's about the same as what I saw with the stock globes. You can install diffusers to take care of that, but then they wouldn't match the hot spots on the power meters, right? <G>

Here it is all buttoned up, for comparison of the two bulb types. The white meters are still incandescent, the rest is all LED. If anything, the LED's give a much more even color wash on the dial. The three original globes, located all the way on the left end of the faceplate (light transmission through the glass), faded quite a bit all the way on the right end of the dial. In case you're wondering, the wheat grain power meter lamps tend to bake themselves into the meter bodies ... best left alone if they're still working.

led-faceplate-done.jpg
 
Final solution was the LEDs ... those are commonly available for automotive interior lamps.

led-wedgie.jpg


.

I just got these LEDs for my Kenwood receiver, which I think is 8v. They work, but unfortunately there's a definite flicker. What would I need to do to rectify (get it?) that?

The Kenwood uses these globe bulbs. All were working, but I broke one trying to remove it :( So I tried these LEDs.

EDIT: I just checked the lamp voltage circuit and it's putting out 6.8v. Seems like it should be higher than that, but maybe with the other three lamps, that voltage is dropping.

The LEDs claim to be for 12v car applications, so maybe the voltage is too low?
 
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7vac is typical on most of the "classic" receivers, so no worries there.

LEDs tend to flicker, some less than others when driven with VAC, and a lot depends on your particular unit and ambient light levels. I got lucky on mine.

Lots of different AC/DC rectifier circuits available, but I like the plug 'n play option. I get these full wave rectifiers off da bay if I see flicker - two wires in, two wires out. Clip the main lighting circuit leads in a convenient spot and some two face tape for mounting.

led-rectifier.jpg


Another nice feature is you can use the stock lighting circuit for both your original VAC bulbs or LEDs, depending on which side of the rectifier you wire them to, and how ambitious you are when relamping.

Just search for "led rectifier" on da bay. First one on the search results.

** Other than the flicker, are you happy with intensity and color?
 
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7vac is typical on most of the "classic" receivers, so no worries there.

LEDs tend to flicker, some less than others when driven with VAC, and a lot depends on your particular unit and ambient light levels. I got lucky on mine.

Lots of different AC/DC rectifier circuits available, but I like the plug 'n play option. I get these full wave rectifiers off da bay if I see flicker - two wires in, two wires out. Clip the main lighting circuit leads in a convenient spot and some two face tape for mounting.

led-rectifier.jpg


Another nice feature is you can use the stock lighting circuit for both your original VAC bulbs or LEDs, depending on which side of the rectifier you wire them to, and how ambitious you are when relamping.

Just search for "led rectifier" on da bay. First one on the search results.

** Other than the flicker, are you happy with intensity and color?

I'll look into the rectifier, thank you. Frankly I also prefer a single-package design. Seems like this is what I want:

https://www.superbrightleds.com/mor...d-led-tower-miniature-wedge-retrofit-car/910/

But not $7 each and not that size. Couldn't they just pair up the diodes and reverse half of them so there is no apparent flicker? I even entertained the notion of rigging up a 12v wall wart to run just the lamps :)

Are there any other plug n play LEDs that I'm unaware of? Seems there are plenty for the fuse-style lamps like this: http://audiokarma.org/forums/index....what-is-your-go-to.679281/page-2#post-9070773

Check out the photo on the left. It says "AC 8V." I'm guessing that tiny IC is doing the rectification. There's gotta be a wedge-style T10 (or whatever) equivalent out there.

The brightness and color is okay. I'm mainly just looking for a cheap and easy replacement.
 
Zone Tech 5-smd Warm White High Power LED Car Lights Bulb

The bases slip right off, and you should be able to use the OEM bases from your globe bulbs. Those slip right off on the Sansui lamps anyway.

led-wedgie.jpg


Check the lamps in the lower left pic - right one uses the original rubber bulb boot without mods, and the left one has the cup sliced off to move the LED bulb back from the meter for a better spread.

led-lighting.jpg


One pleasant surprise on my 9001 - the LEDs fit perfectly into the original colored bulb shields used to color the dial glass.

led-lighting-dial-shields.jpg
 
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