Philips GA212 power switch and bulbs questions

[Puddintane]

Hello all. I've read most (if not all) the posts concerning Philips 212 TTs, and I have a couple questions that aren't addressed specifically elsewhere. I bought my 212 new approx. 30 years ago, the last 15 of which it's been stored in the box. It works well, for the most part. The speed control lights don't all work as they should (what else is new!), but the speed controls do work--at least the 33 does. The 45 is erratic: it tends to want to go back to stop. But I don't play 45s, so it's no big deal for me other than the general annoyance that the light doesn't work right (I tend to use it when dusting before playing). The 33 bulb is burned out, but it doesn't affect the speed--it runs just fine at 33. The power button works too, but it's very sticky and doesn't always want to lock down when pressed to turn the unit on or pop back up when turned off.

As for the power switch, I read in a series of posts about restoring a Pioneer tt on AudioKarma (see here), that you shouldn't use Deoxit in the power button (it's supposedly not for high power switches). Does that apply the same to the type of switches used in the Philips?

And as to the lightbulbs, I read a post on AKthat mentioned a lightbulb supplier (Donsbulbs.com) that has bulbsthat supposedly work. Apparently the inflation rate for this bulb has been particularly severe: $10.25 USD a little over a year ago, and $16 each today. Ouch!!! The whole tuneup kit that's sold on that well-known auction site is only $49, and it includes three bulbs, a belt, a manual, and a power switch! Anyway, I've searched other bulb sellers for identical or similar bulbs, and because I'm electronically challenged, I don't know which specs are critical.

In other words, if the specs for the bulbs at Donsbulbs are correct, and I can only find others that vary slightly in some particular spec, which specs are critical? Obviously, the base has to match (I won't be modding anything, just screwing in a new one that hopefully works properly), but what about volts, amps, watts, filament type, etc? There seems to be plenty of room for a bulb that isn't the exact same shape of globe (the originals are fairly straight along the sides, but some I've found are more of a round shape [when viewed from the side], but which of the others really matter? Or are minor variances in some of those specs acceptable?

[AsmJunkie]

Hi Puddintane,

I just restored my GA212 to operating condition a few months back. I also could not find the right bulbs and also had problems with the power-switch. I also had to deal with a belt that had melted to the inner-workings.

I took the power-switch out, took it apart and cleaned it with isopropyl alcohol. It works much better, but is still a little sticky. A kit with a new power-switch sounds worthwhile to me.

If you do pull out the isopropyl, try it on the three touch-buttons. I found that when grease from your fingers builds up, they get unreliable. The symptom that I get is that, when you touch either the 33 or 45 button, the light comes on but goes out again when you lift your finger.

There seems to be plenty of room for a bulb that isn't the exact same shape of globe (the originals are fairly straight along the sides, but some I've found are more of a round shape [when viewed from the side], but which of the others really matter?

Hmm. . . My original bulbs were round under the buttons, and "fairly straight along the sides" for the bulb that senses the tonearm position. But even though that is what originally came with the table over thirty years ago, that is NOT what is called out in the service manual. According to the service manual:

33 & 45 bulbs: 6.3v, 44ma, part# 4H134-40331
Stop & sensor bulbs: 6v, 100ma, part# 4H134-40326

If you need a sensor bulb, it should be close to the same brightness as the original .1amp bulb. If it does need to be replaced, you will probably need to readjust the sensor's sensitivity. My original bulb there was a Philips 8073D, which matches the specs in the service manual.

The bulbs under the buttons are less critical. Any replacements should be around 6 volts, but they could be brighter or dimmer than 44 milliamps. My original bulbs were Philips 7121D, which are 50ma instead of 44ma.

I could not find replacement bulbs for under the touch-buttons, so I replaced them with green LEDs.

Hope that helps, at least a little.

Mark

[Puddintane]

AsmJunkie--

Thanks for the reply. That all helps a lot. I've learned a bit more in the last couple hours after digging a little more...

I took the power-switch out, took it apart and cleaned it with isopropyl alcohol. It works much better, but is still a little sticky. A kit with a new power-switch sounds worthwhile to me.

I'm not sure what kind of switch was being referenced in the Pioneer rebuild I mentioned. He recommended using fine-grit sandpaper to bare the metal on the contacts.

..the three touch-buttons. The symptom that I get is that, when you touch either the 33 or 45 button, the light comes on but goes out again when you lift your finger.

That's pretty much what happens with my 45 button.

There seems to be plenty of room for a bulb that isn't the exact same shape of globe (the originals are fairly straight along the sides, but some I've found are more of a round shape [when viewed from the side], but which of the others really matter?

My original bulbs were round under the buttons, and "fairly straight along the sides" for the bulb that senses the tonearm position.

After looking more closely at the info at Donsbulbs.com, I noticed that the rounder ones are called "Gxx" for globe-shaped glass, and "Txx" for tubular-shaped glass (there are others as well). The part number I originally searched for resulted in an 11mm globe-shaped glass; but mine are tubular--at least those under the stop, 33, and 45 buttons. And they're all identical in specs (6.3v, 44ma). Once I realized that and modified my search terms, I came up with a tubular glass bulb in 10mm width that is exactly like mine--and it's half the price of the one I found at first! Yippee!!! (The only problem now is that I also noticed that the min. order is $40--plus $6 S&H, and only one of mine is burned out. I may end up going for the auction-site kit after all). The speed sensor bulb in mine is globe-shaped and higher amps (.1, or 100ma), like you describe for yours.

Stop & sensor bulbs: 6v, 100ma, part# 4H134-40326

If you need a sensor bulb, it should be close to the same brightness as the original .1amp bulb. If it does need to be replaced, you will probably need to readjust the sensor's sensitivity. My original bulb there was a Philips 8073D, which matches the specs in the service manual.

There is one there that is identical in all other specs except for volts: it is 7v and my original (that still works) is 6v. Do you think that will matter? (I.e., I'd prefer plug and play, if you know what I mean!)

[AsmJunkie]

Hi Puddintane,

It sounds like you're making good progress.

He recommended using fine-grit sandpaper to bare the metal on the contacts.

I doubt that will help. The problem with my switch was not with the contacts, but with the plastic mechanical latching mechanism that holds it into the ON position. It would stick. Cleaning it helped a lot, but I think I need to add some Teflon lubricant to get it to work well.

That's pretty much what happens with my 45 button.

Well, here is a test: When it behaves like that, try licking your finger and then touching the 45 button. If that works, then it is behaving just like mine, where the resistance of your finger is not enough to "un-latch" the Stop button. Cleaning the Stop button may help, or you may end up like me, constantly licking your finger. I plan to replace resistors on the circuit board to decrease the sensitivity of the Stop button and increase the sensitivity of the 45 and 33 buttons, next time I have it opened-up.

There is one there that is identical in all other specs except for volts: it is 7v and my original (that still works) is 6v. Do you think that will matter? (I.e., I'd prefer plug and play, if you know what I mean!)

It is hard to say. What is important is that the brightness of the bulb be the same, or you may need to adjust the sensitivity. I had replaced the bulb with a dimmer one, and the motor would no longer shut-off at the end of the album. I adjusted the sensitivity pot, and it now works perfectly. You probably already found the thread about adjusting the sensitivity from about a month ago.

[Puddintane]

I took the power-switch out, took it apart and cleaned it with isopropyl alcohol.

By the way, just how did you take it apart anyway? Did you cut the wires (or desolder them) and take the whole thing out to work on it, or did you just pop the plastic parts open somehow? I just know if I start trying to pry that thing apart its going to bust somewhere!

Do you recognize the beige-colored plastic part in the pics? I found it in among the wires where the power line connects to a block at the right rear. My 212 doesn't have the plug in connector for the power cord; the cord comes straight in (the knot in the cord is wedged into a plastic slot in the bottom cover to hold it in place) and connects to a block (as I believe is described in Addendum II in the service manual) right next to the underside of the tonearm pivot. I placed it back in among the wires for one of the pics, and it's also sitting on the top edge of the cabinet in another. I've looked at the exploded parts diagram in the service manual and can't see anything that looks like it. And it doesn't appear to have broken off--at least there is no evidence from examining all the edges on the piece.

[Puddintane]

I adjusted the sensitivity pot, and it now works perfectly. You probably already found the thread about adjusting the sensitivity from about a month ago.

Actually, no, I haven't seen that one. Do you remember the thread title? I searched for "sensitivity" and "Philips" with no luck. Btw, thanks for all your suggestions.

Never mind! I found it. The holes on the circuit board seem to have a brown papery material covering them (my complete ignorance of all things electronic should be totally obvious here!), and a couple are punctured already. If I were to need to adjust that pot, is it done by inserting a small Phillips-head screwdriver into those holes (assumed from the x-style mark on the schematic)?

Wait! I think I hear Dorothy's friend Scarecrow's song coming on...

[AsmJunkie]

By the way, just how did you take it apart anyway?

There are two screws on either side of the switch that hold it in place. If you remove those two screws, the switch is free to flap in the breeze. If I remember correctly, the plastic parts were able to just slide apart once the switch was loose.

Did you cut the wires (or desolder them) and take the whole thing out to work on it, or did you just pop the plastic parts open somehow?

The wires were held along the inside edge of the enclosure by bendable cable-clips. I simply bent them open to allow me enough wire to move around. I then disassembled the switch and cleaned it with the wires in place.

Do you recognize the beige-colored plastic part in the pics? . . . My 212 doesn't have the plug in connector for the power cord; the cord comes straight in (the knot in the cord is wedged into a plastic slot in the bottom cover to hold it in place) and connects to a block (as I believe is described in Addendum II in the service manual) right next to the underside of the tonearm pivot.

Mine is like yours: The power-cord comes in through a notch in the bottom cover. But I don't seem to have a part that looks like that. It looks like it may be a cable clip of some sort.

If I were to need to adjust that pot, is it done by inserting a small Phillips-head screwdriver into those holes (assumed from the x-style mark on the schematic)?

Yes, or a small flat-blade screwdriver will also work. The adjustment pots are the metal type with a cross-shaped cut-out in the middle that accept almost anything that will fit through the hole in the PCB.

[soundbug1]

Also included in the $50 Ebay kit is the Belt, FOUR bulbs, the power switch replacement, owners manual , schematics and INSTRUCTIONS on how to replace all the parts.

Original service manuals call for a 44mA bulb for the touch button switches...many turntables came direct from factory with 50mA bulbs. Either work correctly

I've been selling those kits on Ebay for nearly 8 years...not a single person has returned a kit nor found it not to work.

Soundbug1

[Puddintane]

Well, here is a test: When it behaves like that, try licking your finger and then touching the 45 button. If that works, then it is behaving just like mine, where the resistance of your finger is not enough to "un-latch" the Stop button. Cleaning the Stop button may help, or you may end up like me, constantly licking your finger. I plan to replace resistors on the circuit board to decrease the sensitivity of the Stop button and increase the sensitivity of the 45 and 33 buttons, next time I have it opened-up.

So let's assume I were to successfully repair/replace the bulb function, and after cleaning the touch controls with alcohol (or frequent applications of spit!) and they still don't work right (e.g., the 45 doesn't hold when touched and switches back to off), is replacing a resistor the only option to restoring the switch's functionality?

[AsmJunkie]

So let's assume I were to successfully repair/replace the bulb function, and after cleaning the touch controls with alcohol (or frequent applications of spit!) and they still don't work right (e.g., the 45 doesn't hold when touched and switches back to off), is replacing a resistor the only option to restoring the switch's functionality?

Probably not. The resistor change simply makes the switch more sensitive. If it is broken, then the resistor change won't help.

To test if it is indeed broken, use something metallic to activate the switch, shorting the outer ring to the inner disk. If that works, then it is a sensitivity issue, albeit a severe one. If that doesn't work, then something in the circuit is not allowing the "stop" to un-latch.

I will look at the schematics to see what can cause that.

Mark

[aabottom]

A thread relavent to my GA312.

[Puddintane]

Do you recognize the beige-colored plastic part in the pics? I found it in among the wires where the power line connects to a block at the right rear. My 212 doesn't have the plug in connector for the power cord; the cord comes straight in (the knot in the cord is wedged into a plastic slot in the bottom cover to hold it in place) and connects to a block (as I believe is described in Addendum II in the service manual) right next to the underside of the tonearm pivot. I placed it back in among the wires for one of the pics, and it's also sitting on the top edge of the cabinet in another. I've looked at the exploded parts diagram in the service manual and can't see anything that looks like it. And it doesn't appear to have broken off--at least there is no evidence from examining all the edges on the piece.

I'm not sure why those pics aren't showing. But here they are again, followed by a little discovery I made today.



I had laid aside the Grado cartridge while I was fiddling around with other things inside the 212. When I picked up the cart to look at something, the light went on. The shape reminded me of that little plastic part, and the fit and plastic color are too similar to be coincidental. It must be a sort of stylus protector. And as I was looking at the scratches on the tt top (the "plinth," not the dustcover), it reminded me of one time long ago when I had packed it up for a move. When I unpacked it I realized that I had forgotten to put in the transit screws (and to remove the platter, too). Well, the box must have gotten flipped over, and so the platter had come off the spindle and was sliding around. I can only guess that this "stylus protector" (if that is, in fact, what it is) got knocked off too in the process and could easily have fallen through into the cabinet. Here's the cart with the "protector" in place. What do you think?

[Alec124c41]

Yes, that is the Grado stylus guard.

Cheers,
Alec

[Puddintane]

Yes, that is the Grado stylus guard.

Cheers,
Alec

Obviously not meant to be installed while the cart is attached to the tonearm. It does not go on or off very easily even when holding the cart and headshell in hand --it's a very snug fit. But I suppose if you bang it with the side of a platter it will pop right off!