The PHILCO Phorum
Model 70 - Printable Version

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RE: Model 70 - vecher - 01-07-2018

Have a question.. My radio doesn't have the .09 Cap # 40 that is across the 2 Filter caps 6 UF # 41 and # 38..

I know schematic says not used on all models.. But how do you know what models it was used on..

Is it really necessary?

[Image: https://farm5.staticflickr.com/4690/24681477527_837e1c1858_b.jpg]



Skip...

RE: Model 70 - klondike98 - 01-07-2018

That cap is used on units with serial numbers less than B22000. See: http://www.philcoradio.com/images/phorum/schem/70a.jpg (early 70 version schematic)
vs the later version schematic http://www.philcoradio.com/images/phorum/schem/70b.jpg

RE: Model 70 - Steve Davis - 01-07-2018

A capacitor used in this fashion is of doubtful usefulness. If the radio originally had cap 40, my advice is leave it out and up capacitors 38 and 41 to 10uf. The idea was to create a tuned circuit to trap out the 120 cycle ripple. The problem with this is, if the capacitor is off value, either high or low, it will actually increase  hum. Other models used this capacitor also, I always omit them.

Steve

RE: Model 70 - Ron Ramirez - 01-07-2018

(01-07-2018, 12:17 AM)vecher Wrote:  I know schematic says not used on all models.. But how do you know what models it was used on..

Simple...first look it over carefully. Does your radio seem to match the early or late schematic? Does your radio have any 35/51 tubes, including one as audio amplifier? If so it is a "late" version (above S/N B22000). Otherwise it is an "early" version (below S/N B22000).

At some point in early 70 production, capacitor (40) was removed as the bean counters at Philco deemed it unnecessary. As to when, I do not know. We could figure it out, but it would require everyone owning an early 70 to be willing to share their 70's serial number. As you know, that isn't going to happen, so why worry about the little things? Just know that your 70 was likely built after the bean counters declared that part (40) in your set was not necessary, and was no longer installed. Icon_smile

Edit: Steve answered as I was typing, and his answer is better than mine. Ditto what he said. Icon_thumbup

RE: Model 70 - vecher - 01-07-2018

Ok Thanks all.. My caps do not have any values on them Just says Sprague Condenser with a serial number on it..

So I assume they are 6 uf .. Looks like the .09 was never installed in this set.

Anyway to know what value they really used? I tried measuring them but got no reading on either so before i order caps what should i use..

I know not to use Electrolytic .


My Serial number is I think 344865 on back of chassis..

Thanks

Skip

RE: Model 70 - vecher - 01-10-2018

Ok Here we go.. HELP HELP..

I was attempting to re stuff my 2 Caps.. But stupid me cut in wrong place.

Here is original cap..

[Image: https://farm5.staticflickr.com/4651/38719107035_4aff6c6bf7_b.jpg]

I cut the wrong side..

[Image: https://farm5.staticflickr.com/4746/38719109495_4bd3a3d241_b.jpg]


[Image: https://farm5.staticflickr.com/4665/38719110045_3d57e34527_z.jpg]

Question is ... How do I reattach them The rubber in side is very hard and of course they do not fit together well. Is there some tool I can use to chip out the rubber on side so it will fit?  

Hopefully someone did this before Not just me..

Thanks
Skip

RE: Model 70 - Steve Davis - 01-10-2018

Skip, the original capacitor were 6uf, I would replace them with 10uf.

Steve

RE: Model 70 - klondike98 - 01-10-2018

Skip, here's a thread on how I did my Sprague caps. I ground off the bottom crimp and pulled the guts out the bottom. In your case, that's not really an option any more but maybe it will give you some ideas. If I recall correctly I think Phlogiston has also soldered this type of cap back together and then smoothed the joint ....

RE: Model 70 - vecher - 01-10-2018

Ok, Thanks That will help I think.. Not really sure how the 2 pieces go together though..

On the 10 Uf caps replacement Will 6.8uf work? I do not have any 10 UF Solens in stock..

Skip

RE: Model 70 - morzh - 01-10-2018

If 6uF worked, 6.8uF will also work.

As for re-attaching, the case is copper, should be able to solder it back if this what you want to do.

The "rubber" on these is incredibly hard. I dented my chisel on it.

RE: Model 70 - klondike98 - 01-10-2018

I don't see the need to take the rubber out...

RE: Model 70 - Warren - 01-10-2018

If you want to take some of the hard rubber out to make the 2 parts fit, do you have a dremel tool? Sounds like the easiest option.

RE: Model 70 - vecher - 01-11-2018

Yup Thats what I did.. Fits good now.. Didn't make same mistake with other one.. That worked good..

Skip..

RE: Model 70 - vecher - 01-11-2018

Ok,, Next BIG Goof.. I broke off the top of the fine tune adjustment on main Tuning Capacitor.. The middle.. It was rusted and when tried to move it it snapped..

How do I fix???? Or do I need a replacement Tuning Cap..


[Image: https://farm5.staticflickr.com/4762/38729079925_31bff841ef_b.jpg]


This is getting to be a big money pit.. Getting very frustrated..

Please Help..

Skip..

RE: Model 70 - Steve Davis - 01-11-2018

Skip, if you want, you can send the tuning condenser to me,  I will repair it for you. It will only cost postage.

Steve