I finished my 40-145 re-cap (and a the bad resistors), and it fires up good (isolated, slow up on the AC, no smoke, tubes good). Still trouble shooting a few things, like the $%^&* push buttons. Just very dirty, I think. I know to use the manual "tune" button.
Question: When I looked at the Rider alignment instructions, the RF alignment calls for an "Alignment Adapter". The unit is Loctal tubes. I happen to have a "Thru" Loctal adapter from - somewhere, no markings. Anyone have any info on what the Philco "Alignment Adapter" hook-up is? Mine has these, but I'm willing to modify it:
Black wire: to pin 4 of the 1232/7G7 (RF) TUBE only, not thru to the receiver socket.
White Wire: to pin 2 of the Receiver socket ONLY (not thru to the tube). It's loose, so needs repair anyway.
Green wire: to pin 2 of the TUBE only (not thru to the receiver).
White and green wires in series with an ammeter would be handy for measuring plate current on the 1232/7G7 (and many other Loctal tubes).
That makes no sense for the way it is called out on the alignment instructions. BTW: the black wire would be to the G3 (suppressor) of the tube (pentode).
The alignment instructions also call for it's use in on the 7C6 second detector for A.V.C. measurement.
I can probably noodle it out, but I'd rather not fry something (the 1232/7G7 is already low performing!).
Anyone got one of these little puppies? And can advise the pin outs. Or recommend some? (data attached)
P.S. Tore down the adaptor, had to fix White lead anyway. Above pins correct, PLUS these inside the adaptor:
1) pins 3, 6 & 8 connected thru (tube to socket).
2) 3.0 Meg resistor pin 4 to 6
3) WORST ISSUE: pins 1 & 8 shorted! These are filament on the 1232/7G7 and many (most?) Loctals. Might be of some interest (?) on a series filament rig, but the 40-145 is transformer equipped. With no fuse in the unit (only on the bench) this could have been ugly. This "adaptor" was clearly not meant for the 40-145 or anything similar. Glad I didn't just "try it". Never measured pins 1 to 8 before tear down. Never thought to check that!
Anyone know how a Philco "alignment adaptor" is supposed t be wired? I might fix it up to that, if I can.
I think the idea was to have the tubes (two) installed in the unit, thru the adaptor, with the fancy antenna system hooked up, so you can do the RF & IF alignment that way, mostly installed in the case.
Sorry Dale, but I don't know what that means. Do you mean a straight thru test adaptor, with contacts for all the pins? Thanks anyway.
The procedure calls out use of light colored wire and black wire "which protrude from the side of the adaptor". I would like to know what pins the "light colored wire" and the "black wire" connect to, so I can modify a different "alignment adaptor" (as Philco calls it) that I have.
If no one has the info, I can just noodle it out, or use what I would normally use without any specific procedure / hookup.
I would do the normal process of alignment out of the cabinet and delay using the adapter until the setup has been finalized. No harm in doing it by the book later.
I have a number of Philco test equipment and accessory catalogs, and I don't see an "alignment adapter" in any of them. I have the manuals for many items of Philco test equipment, have looked through all of them, and see no reference to an "alignment adapter" in any of them.
Thanks, Dale. Odd, but I just remembered that although the data has Philco all over it, it is still Rider distributed data. A small error is always possible, even though the Rider data always looks great.
klemer Wrote:...although the data has Philco all over it, it is still Rider distributed data.
All that John Rider did was to collect and reprint service information from the manufacturers. Compare what he published for the 40-145 with the original Philco service information in the Philco 1940 RMS Year Book, pp. 53-54.
Looking at the alignment instructions, it is suggested that alignment may be performed with an output meter connected across the speaker voice coil.
It is not mandatory that a VTVM be used with an aligning adaptor (and there may no longer be any in existence, and if there is, whoever has some stashed away may not know what they are for).
Use of the VTVM will, however, result in a more precise alignment provided that modern equipment such as a function generator, which does not drift, used with suitable attenuators as needed is also used.
Now comes the mystery of just exactly what an "aligning adaptor" was, and where those light and black wires connected internally in the adaptor.
We can easily ascertain that this adaptor had a loctal base, and a loctal socket on top, with each pin of the base connected to the corresponding socket connection on top. That is to say, pin 1 of the base to pin 1 of the top socket, pin 2 to pin 2, pin 3 to pin 3, etc.
The real mystery lies in where those light and black wires would have connected in the adaptor.
To figure that out, careful study of the schematic is called for.
We know from the scant information given in the alignment instructions, that the VTVM is intended to measure AVC voltage, which is a negative voltage.
Now we need to know which connections this aligning adaptor would have used which would have measurable AVC voltage in common so the adaptor could be used with two tubes with completely different pinouts.
Looking at the 40-140/40-145 schematic, we see that AVC voltage will be present at one of the 7C6 diode plates which is either pins 5 or 6. We also see that AVC voltage will be present on the 1232 control grid, pin 6. To measure AVC voltage with such an adaptor, a provision for a "low" or "ground" connection must also be provided.
On the 40-140/40-145 schematic, the two tube pins which have AVC voltage in common are - pin 6 for AVC high, pin 7 for AVC low or ground.
Therefore, a Philco "aligning adaptor" would have had a loctal base, a loctal socket on top, and wires connected from each pin of the base to the same corresponding pin on the top socket, plus - the "light" wire to pin 6 of the base & socket, and the "black" wire to pin 7 of the base & socket.
See image below.
Without an aligning adaptor, if you want to use a VTVM to measure AVC voltage, you may simply connect the "high" end of your VTVM to pin 6 of the 1232 (under the chassis) and the "low" end of same to pin 7 of the 1232 for IF alignment.
For RF alignment, connect the "high" end of the VTVM to pin 6 of the 7C6, and the "low" to chassis ground.
Or just use an output meter across the speaker voice coil and be done with it.
It sounds like the loctal adaptor you have is not the same as the Philco aligning adaptor as described in the Philco 40-140/145 service info.
I see yours only has pins 3, 6 & 8 connected through, pin to corresponding contact on socket, plus a 3 meg resistor between pin 4 and pin 6 of the socket. Also pins 1 & 8 shorted. Not good.
What you want is something which has every pin connected to every contact of the corresponding socket. (In other words, "straight through" as you have stated.) Otherwise, the radio will not work when you attempt to use it as an aligning adaptor. Not to mention the direct short across filament pins which would potentially take out the power transformer.
To find a loctal test socket adapter (aka a straight through adapter, which is probably what Philco specified for that radio as Ron pointed out) search for "loctal test adapter" without the quotes on the auction site. The military U-103/U adapters normally sell for $20 to $30, and they are extremely well built (your tax dollars at work). I have a few military test socket adapters.
Thank you Dale & Ron.
Very thorough analysis & reverse engineering, Ron! Love it.
Glad I didn't even consider "just trying it". Lesson learned years ago.
I have a good Simpson audio output meter, and can use that and normal signal generator hookups. I just went down a "rabbit hole" since Philco said using their Alignment Adaptor and a VTVM (which I also have) was "a very sensitive indication of A.V.C. voltage". Now I wonder which is better. I have a Loctal socket on the way here, that will make a better thru Loctal test adapter with pin-outs all around. The one I had didn't survive teardown; I HATE epoxy (or equivalent) sometimes! I like to make my own adapters, rather than buy one from eBray if possible. Will advise output vs A.V.C. voltage!
Thanks all!
