what the heck is this thing? heeeellllllpppp!!! r.g.?

[pinkjimiphoton]

hi, working on the phase II...there's two of these on the left side of the pedal board part, both are dead...this one had one of the leads broken off..
any idea what it is? the larger part is the same size as a 5mm led, the smaller part is about 4mm...

is it a lamp, or a primitive led? i tried a 5mm led in it, but the led burned out, made the good ones flash before it died. no, i didn't put a current limiting resistor in line with it, i just wanted to see if i could run an led with the disconnected wires..everything is kinda daisy chained, so it's tough to figure out.

before i go screwing something up, i figured i'd better ask...appreciate the help!!

[R.G.]

It's a miniature incandescent lamp. That's why the LEDs burned out - way too much voltage and no current limit. I think it will be obvious if you trace the wires back into the board. One of the wires is even listed as "bulb resistor" or some such as I remember. What's confusing you is probably the plastic shell it's in. You may be able to get the glass bulb back out the wire end. Maybe. We'll work out how to use LEDs there in the future.

LEDs were **hot** new technology when this thing came out, not to be used indiscriminately.

[pinkjimiphoton]

is this what they call a "grain of wheat" lamp then? do you think it's something i can get at mouser perhaps?

thanks r.g.!! 

[R.G.]

is this what they call a "grain of wheat" lamp then? do you think it's something i can get at mouser perhaps?

Yes. See:
http://www.mouser.com/catalog/catalogUSD/643/111.pdf

Also see
http://www.mouser.com/APM-HEXSEAL/Optoelectronics/Lamps-Holders/_/N-5g6pZ1z0zlgjZscv7?FS=True
for some plastic lamp holders for T- 3/4, T-1, and T-1 3/4 incandescent lamps.

I don't know that's what that is, but it looks suspiciously similar and may be a usable replacement.

[Govmnt_Lacky]

A few questions:

1) Is there a lead missing from the lamp?
2) Do you know what kind of voltage fed the lamp? (i.e. 5V, 12V, etc.)
3) Can you peel off the Red rubber coating to see exactly what the LAMP looks like?
4) If the voltage is appropriate, couldn't you just replace it with a diffused Red LED and experiment with drop down resistors until you get the right "brightness range?"

My 2 pence... 

[wavley]

I had to replace a white one of these in a space echo recently, I can't be much assistance on finding one being that I got lucky and had one in an old box of random parts (and my wife wonders why I have those things)

[pinkjimiphoton]

hi guys, i picked up some exact replacements at cables and connectors, they are 5 volt "grain of wheat" lamps with leads, and they just barely will fit into the original translucent plastic covers. i figured out why they didn't work on the left side...they're wired in parrallel so when one goes out the voltage goes up, and took the other lamp out. so i got two of 'em...about 2 bux for a package of two.

www.cablesandconnectors.com

they have some worthy, if rare, stuff.

now...i didn't have the forethought to measure the voltage prior to hitting the parts store, cuz it was an afterthought stopping there (had to bring my girl to the doctor, and it was close)...so i'll check it first...but they are almost exactly the same physical size as the originals, and the size seemed to be dependant on the voltage, so we'll see.

thanks for the advice, r.g. and all....also picked up some more incandescents to fix the light under the "fuzz" switch on the top panel...i figure better to get a couple varietys, and see what works rather than get the wrong thing and keep going back. besides...parts are always useful somewhere, right?

onwards and upwards!!


a little bit closer every day to a functioning unit...

[R.G.]

If you can measure the voltage on the wires connecting to the bulbs, and tell which wires they are on the schematic, I can pick LEDs and resistors to replace them.

[pinkjimiphoton]

well, the voltage is 17 vac. that i can tell...but as to where on the schematic they are connected, that may take a while, i'll have to look at it to try and figure it out...ALL the wires on the switches pertaining to the lamps on the left side are disconnected...i just finished fitting the grain of wheat lamps inside the little plastic covers, and re-mounted them to the pedal board. gonna try and hook them up...even if i blow them up...just to see if i get the wiring right. it's worth the 2 bux, plus i figure i'll learn something in the process...like listening to YOU!

it looks like all the lamps are daisy chained like a string of xmas tree lights on a lite green wire...but it connects at at least 2 points on the board, and one dissappears into the bundle going up to the control panel, too. and this thing's a mess...it works ok, but it wasn't stored well, so i've gotta do a lot of cleaning etc. don't wanna take it apart too much yet til i get the stuff connected, that way if i screw something up, at least i know it was in one piece and working before trying to figure out where all the wires go to.

give me a little while, let me see what i can figure out here. i just temporarily connected the new lamps...they didn't blow out, so so far....wish me luck!!

[pinkjimiphoton]

IT LIVES!!  5 volt grain of wheat lamps, about 2-3 mm diameter...if ya are careful, can get the old blown lamps out, and slide the replacements right in...done deal!!



part number ml-683 t-1 standard wire terminal 5.0 volts .060 amps "aircraft lamps" by gc electronics .  $2.59 for a pair.

[R.G.]

The grain of wheat bulb sizes (T-3/4, T-1, T-1 3/4) is where the LED bulb size comes from. T-1 LEDs are 3mm diameter, T 1 3/4 LEDs are 5mm diameter.

[pinkjimiphoton]

thanks, r.g. learn something new every time you post!!!

well, one more question answered, one more piece added back to the pie!!

onwards and upwards!!