HOwdee...
I'm happy because I just bought this neato Optonica SM1515 integrated amp.
But I'm unhappy because the meter lamps were blown and replaced by someone who put 12V fuse lamps in their place...which, of course are incorrect and won't illuminate.
So... now I have the distinct pleasure of trying to figure out what the original lamp values were. I have the service manual, which specifies the part number but not the value.
I have done my homework and what I do know is that they are 6.3vdc bulbs....but the problem is... I need the amperage.
6.3V @ ??mA
Thanks, yawl!
I'm happy because I just bought this neato Optonica SM1515 integrated amp.
But I'm unhappy because the meter lamps were blown and replaced by someone who put 12V fuse lamps in their place...which, of course are incorrect and won't illuminate.
So... now I have the distinct pleasure of trying to figure out what the original lamp values were. I have the service manual, which specifies the part number but not the value.
I have done my homework and what I do know is that they are 6.3vdc bulbs....but the problem is... I need the amperage.
6.3V @ ??mA
Thanks, yawl!
Louie- Its probally not very critical. I would go get some 6..3V lamps and install them. If the current avaiable is enough the lamps will light. At the same time you can measure the amount of current drawn. I would check a major parts supply like DigiKey, or for that matter your local hardware store. My local Ace Hardware has a selection of lamps. Look for lamps that are intended for flashligh use. The current required is likely to be small.
Thanks.... yes, well.... I tried a 6v flashlight bulb and the amp would not light it. A 9V battery did light it, alot, and two AA batteries lit it up about half way.
But the amp would not make it glow at all. I even measured at the bulb while it was connected to the amp and the tester said 6V, just like without the bulb, but no glow.
mystery
Last edited:
Usually the lamps have their own winding on the transformer, and their own fuse. Normally it will be rated at just above the total value of the lamps. For example, a 250mA fuse for two 100mA bulbs. The fuse might even be blown, in your case, if you aren't getting any light at all.
ok... but, there IS 6 volts being delivered to the wires that lead to the lamps, so if the lamps DO have their own fuse, it's certainly not blown, unless I'm misreading things completely...but thanks for the theory concerning the fuse and the Xformer. I gather from what you say, that provided there is a fuse, I can simply divide the fuse value by 2 (the number of bulbs) and get the appromimate amperage of a single bulb. I hope that works... thanks!
Last edited:
Ok...thanks again to Coconuts 500 (is that a racetrack in Hawaii??) Jk...
I think we're getting somewhere now. Take a look at this...from the circuit diagram of the Optonica SM-1515 Service Manual.
Location F801, looks like this -o~o-..., shows a fuse spec of 315mAT !! Hurray!
Not sure what the T stands for, but until I hear otherwise, I'm calculating that 315 divided by 2 equals 157.5mA per bulb.
And, because the total fuse value is slightly more than the combined bulb values, I'm guessing the original bulbs to have been something like 6.3v @ 150mA.....
Right ?
I think we're getting somewhere now. Take a look at this...from the circuit diagram of the Optonica SM-1515 Service Manual.
Location F801, looks like this -o~o-..., shows a fuse spec of 315mAT !! Hurray!
Not sure what the T stands for, but until I hear otherwise, I'm calculating that 315 divided by 2 equals 157.5mA per bulb.
And, because the total fuse value is slightly more than the combined bulb values, I'm guessing the original bulbs to have been something like 6.3v @ 150mA.....
Right ?
Last edited:
Sounds about right. Also you could replace the bulbs with some nice bright LED's You would need a series resistor in the low ohms value. Led's typically run about 1.2 to 1.7 V.
"RadioShack 4609703 5mm High-Brightness White LED (2-Pack)
$2 online, $2 nearby
"RadioShack 4609703 5mm High-Brightness White LED (2-Pack)
$2 online, $2 nearby
firecheif thanks...I may do that... but first....
New heartaches. I attached a nice new working #47 lamp bulb (6.3v 150mA) to the lamp leads reading 6.3v strong... and NOTHING. My DMM reads 6v at the wires and my 9v battery lights the bulb. But no go.
So..... I started seeing about the fuses and discovered that the leads do not run to the fuse as illustrated in the diagram in the service manual.
My mistake for using a service manual for the SM-1515H. I have an SM-1515.
I assumed, incorrectly, that the wiring for the lamps would be so simple as to not be any different between these to models. Wrong.
So, I started looking at the part number.
Rlmpm0062Afzz
now, if I'm reading this correctly, the lmp represents 'lamp', m represents 'miniature' and the 006 stands for 6V...so, maybe the 2A stands for 2amps...no idea what the fzz is.
Would anyone concure with this ?
2 amps is pretty beafy for a dial lamp, don't ya think ?
On the other hand, the existing fuse in my amp that is where the 'other' amps lamps connect to is a 4a fuse. So that sort of follows..since two 2a bulbs would equal that fuse. But as close as I can tell, that 4A fuse is the main power fuse as it connect directly to the AC outlets.
Sorry for all the confusion. There doesn't seem to be an SM-1515 service manual online. Just the SM-1515H....🙁
New heartaches. I attached a nice new working #47 lamp bulb (6.3v 150mA) to the lamp leads reading 6.3v strong... and NOTHING. My DMM reads 6v at the wires and my 9v battery lights the bulb. But no go.
So..... I started seeing about the fuses and discovered that the leads do not run to the fuse as illustrated in the diagram in the service manual.
My mistake for using a service manual for the SM-1515H. I have an SM-1515.
I assumed, incorrectly, that the wiring for the lamps would be so simple as to not be any different between these to models. Wrong.
So, I started looking at the part number.
Rlmpm0062Afzz
now, if I'm reading this correctly, the lmp represents 'lamp', m represents 'miniature' and the 006 stands for 6V...so, maybe the 2A stands for 2amps...no idea what the fzz is.
Would anyone concure with this ?
2 amps is pretty beafy for a dial lamp, don't ya think ?
On the other hand, the existing fuse in my amp that is where the 'other' amps lamps connect to is a 4a fuse. So that sort of follows..since two 2a bulbs would equal that fuse. But as close as I can tell, that 4A fuse is the main power fuse as it connect directly to the AC outlets.
Sorry for all the confusion. There doesn't seem to be an SM-1515 service manual online. Just the SM-1515H....🙁
I zoomed over to RShack and snagged the LED pack you recommended. The package specs tham at 25mA and 3.3 to 3.6 volts..
I have lots of R's laying around here.... what value would you recommend ?
Anyone
I have lots of R's laying around here.... what value would you recommend ?
Anyone
well 25 milliamps = .025 amps so ohms law is r=e/I or 150 ohms. If you measure the 6.3volts is it DC? if so you might have to try reversing the polarity, but Ill bet its AC so it won't matter.
If that works you might consider using two LED's in series with no resistor. That should be fine two.
OK...that's where I fall short. I don't know if the lamp leads are AC or DC, because my DMM doesn't tell me. The voltage setting is AC/DC combined and the display just stated the valued 6.3v
That's one feature of the DMM that I never liked. I have a feeling that it's AC.
I'm sure I have some 150 ohm R's here....
So you're saying that polarity won't matter to the LED's, if the 6.3v is AC...right ?
*sigh* 😱
Last edited:
THanks so much... I hope you're around tomorrow, because I had to move this project off the bench, for the time being. Got other fish to fry. 
But yeah... I'll go for it. I'm guessing it doesn't matter which side of the LED the R is attached to. I'll get it one way or nuther.😉
L7
But yeah... I'll go for it. I'm guessing it doesn't matter which side of the LED the R is attached to. I'll get it one way or nuther.😉
L7
T means slow blow type fuse.
315 mA fuse, probably means 2x 100mA bulbs, that is a very common value in these old amps. 2x150 (300mA total) would be a bit too close to the 315mA rating.
Too bad it was the wrong amp.
I think you are doing something wrong. Have you tried following the two wires? Do they both lead to the transformer (via a fuse, probably)?
The lamps cannot be 2A. That would make them 12W lamps. That's too much. Unfortunately, those numbers could mean anything (or nothing).
Problem with the LEDs is that they don't spread their light well at all, if you point them forward, there will be a bright round spot, and if you point them downward, there will be a fairly straight beam of light downward. Not like a bulb, where the light is spread across the entire area it sits in. Also, the light will be much colder than originally, which might not look so nice. This is of course a matter of taste, though.
Also, unless you use a bridge rectifier, the LEDs will flicker quite visibly. This is because the bulb winding definitely is AC. Bulbs don't care. LEDs do. 🙁
315 mA fuse, probably means 2x 100mA bulbs, that is a very common value in these old amps. 2x150 (300mA total) would be a bit too close to the 315mA rating.
Too bad it was the wrong amp.
I think you are doing something wrong. Have you tried following the two wires? Do they both lead to the transformer (via a fuse, probably)?
The lamps cannot be 2A. That would make them 12W lamps. That's too much. Unfortunately, those numbers could mean anything (or nothing).
Problem with the LEDs is that they don't spread their light well at all, if you point them forward, there will be a bright round spot, and if you point them downward, there will be a fairly straight beam of light downward. Not like a bulb, where the light is spread across the entire area it sits in. Also, the light will be much colder than originally, which might not look so nice. This is of course a matter of taste, though.
Also, unless you use a bridge rectifier, the LEDs will flicker quite visibly. This is because the bulb winding definitely is AC. Bulbs don't care. LEDs do. 🙁
OK... now I AM getting weirded out.
I hooked up an LED in series with the 150 ohm R and got nothing.
So I removed the R, nothing.
I hooked both LEDs with their Resistors.... nothing.
Then I hooked both LEDs up without the R's and nothing....................
THEN, I darkened the room and noticed that the LEDS were lit, but just barely. I mean, only enough to where you'd notice in the dark, but not enough to notice with the room light on....and certainly not enough to illuminate the output meters.
Seriously... I have never had this much trouble with something as simple as dial lights. I've installed dial lights in Tandbergs, Teacs, Fender amps...etc etc.... no problem. You hook them up and they burn.
I say again, there is a strong 6.3V at the leads coming from the CB. Two sets of parallel leads, each with 6.3 volts just sitting there waiting to light a freakin' bulb.
But nooooooooooooooooooooooooooooooooooooo!
I hooked up an LED in series with the 150 ohm R and got nothing.
So I removed the R, nothing.
I hooked both LEDs with their Resistors.... nothing.
Then I hooked both LEDs up without the R's and nothing....................
THEN, I darkened the room and noticed that the LEDS were lit, but just barely. I mean, only enough to where you'd notice in the dark, but not enough to notice with the room light on....and certainly not enough to illuminate the output meters.
Seriously... I have never had this much trouble with something as simple as dial lights. I've installed dial lights in Tandbergs, Teacs, Fender amps...etc etc.... no problem. You hook them up and they burn.
I say again, there is a strong 6.3V at the leads coming from the CB. Two sets of parallel leads, each with 6.3 volts just sitting there waiting to light a freakin' bulb.
But nooooooooooooooooooooooooooooooooooooo!Hi, in case anyone else runs into this. 6v 100mA bulbs from radio shack worked for my repair. Catalog #: 272-1142.
Had to also replace R525, R526, R520, and R701. All these resistors were open.
I took photos. The amplifier has a bottom removable panel to access the PCB, and it has the schematic part symbols printed on the bottom and top of the PCB.
My repair details: Optonica SM-1515b Stereo Amplifier | Electromagnetic Publication
Had to also replace R525, R526, R520, and R701. All these resistors were open.
I took photos. The amplifier has a bottom removable panel to access the PCB, and it has the schematic part symbols printed on the bottom and top of the PCB.
My repair details: Optonica SM-1515b Stereo Amplifier | Electromagnetic Publication
- Status
- Not open for further replies.