[Jake Blake]

Can someone tell me what size the nuts are, holding in the speaker of a 610 B ?  I'm giving directions to an Ebay seller.  Thanks.

[mikethedruid]

Tell them to be VERY careful removing the speaker. I believe the nuts are 6-32. Take the nuts off from the back, then push the screws out from the back pushing forward, leaving the speaker in place. If the speaker seems stuck to the front board it probably IS. If it is, then very carefully pry the edges loose from the back by pushing something thin under the rubber or fiber ring between the ring and face board, or the ring may separate from the cone and damage the speaker. I learned this the hard way.

[Jake Blake]

Thanks Mike. 

Sheesh!  I didn't even think about sticking.

The seller is acting like he wants to do this for me, but a little unsure of himself, asking for "tips" for removal. . . . .so I'm trying to compose directions  for him.
While I was waiting, I went into the back of the 89 B here. . . . but I can't figure out which of 3 sizes of nut drivers fits those nuts properly.  Now bear in mind, I've  already removed this speaker once, almost 30 years ago to change the grill cloth, but I guess I must have just used a pair of pliers. 
The 1/4" and 5/16"  nut drivers I have now, appear too small, and the 3/8" is too big.  Maybe I ran into this problem then, because I discovered, mine are only on hand -tight anyway.

What gives? Surely, they are not metric-sized ! 

[Jake Blake]

I guess they're 11/32" !   I don't have an 11/32" nut driver !

[Jake Blake]

Just FYI,  the seller has discovered the nuts and bolts on his specimen are also only hand tight.  He hasn't said one way or the other about a sticking problem.  Yet.  

[Jake Blake]

Just FYI Mike,  the seller of that 610 did get the speaker out ok.  I decided to let him go on and cut the wires to simplify crating the thing.  I believe I can figure out the wiring later.  I may make an effort to obtain some new, period-accurate wire.

[mikethedruid]

You'll need white, green, and green with white tracer. I used cloth covered green 20 ga. and white cloth covered 20 ga. I couldn't find green with a white tracer, so I just masked the green with tape, leaving a gap every inch or so, and shot it with white rattle can paint. It worked out fine.

[Jake Blake]

Okay.  Who's the supplier for that wire?

[mikethedruid]

Last time I bought it in kits but I can't remember where. Here's a link to the same stuff by the spool. I've bought it here too.https://www.tubesandmore.com/products/wi...cover-600v

[Jake Blake]

Thanks Mike !
  I got the 'rattle can' paint.  
Seller has shipped  the radio. I'm supposed to get it  Friday.

[rfeenstra]

Radio Daze for the white and green.  Rhode Island Wire for the wire with tracers.  Unfortunately, the RIW is 18 AWG so a little thicker. Neither is as thin as the original.

   

[Jake Blake]

Thanks for that reference bud.  I'll bear them in mind.
20 gauge wire seems kinda small anyway for a high voltage ( the power output to the primary of the output transformer, and the B+ voltage to the field coil) like that.  Maybe  low current makes the difference.

[rfeenstra]

The gauge of the wire is important for the current it carries. Since the current is only a couple of hundred milliamps (max out of an 80 is less than 150 mA), even thinner wire would work. The hi voltage requires adequate insulation value. The RIW is only rated at 50 volts. I've tested it at about 600 volts AC with no ill effect. I suspect it is better insulation than the original with cracked rubber inside the cloth.

[Jake Blake]

You tested it !!! . . .wow!...I'm impressed!   Ok bud.  Thanks for the info.   I'll post some pics of that 610 when i get it.

[mikethedruid]

20 ga. wire is rated for up to 11 amps for chassis wiring, although I would never use it for more than 6 amps. The currents in tube circuits in our radios and amplifiers are far below that, usually well below 1 amp, so 20 gauge is actually overkill. More important is the insulation voltage breakdown. I have found that all the modern cloth covered wire I have tested made these days is fine for any voltages they encounter in our sets.