The PHILCO Phorum
Philco 89 / 19 transformer (and other bits.) - Printable Version

+- The PHILCO Phorum (https://philcoradio.com/phorum)
+-- Forum: Philco Radio Discussions (https://philcoradio.com/phorum/forumdisplay.php?fid=5)
+--- Forum: Philco Electronic Restoration (https://philcoradio.com/phorum/forumdisplay.php?fid=8)
+--- Thread: Philco 89 / 19 transformer (and other bits.) (/showthread.php?tid=2513)


Philco 89 / 19 transformer (and other bits.) - Guest - 08-01-2010

Hi Guys, this is my first post on this Phorum, so please be gentle.

I have in the past worked on quite a few Australian made Philco radios, these shared some parts with U.S. made radios (knobs, cabinets etc) however I've been asked to repair a 89 / 19 model, made in the good 'ol U S of A.

The block capacitors had me puzzled until I remembered talking to Ron some time ago and heading off in search of his web site. I found the Philco sites (thankfully) and downloaded the info on block caps, circuits etc. I have a set of Riders manuals on hand so a quick scan of the data and I was set to have a serious play!

Long story cut short is that I have most of the radio sorted with a couple of bits left to tidy up. The power tranny is model 8046-N, not listed on the transformer pages I visited. Not a real worry as the radio is being swapped over to real power (240 volts Icon_wink ) so Ill follow the normal voltage trail and pick a suitable Oz transormer to do the job. There are a couple of other differences in that there is no capacitor block 7625-D shown on the parts overlay, this sits next to the wire-wound back bias resistor. Still working out how the caps are wired into that one as there are two circuits showing different ways of wiring the tone caps from the plate. Both show the bottom end of the caps going to the top end of the back bias resistor, however in circuit they are returned straight to chassis ground by the mounting screw. Am I missing something on this one?

I have to say that the set is pretty cramped to work on. To add some pressure all the wires are losing their insulation so a full rewire with appropriate cloth-covered wire may be coming up.

I should have a tranny in place in the next couple of days, then will come the slow power up and no doubt some serious questions for the brains behind this great site.

Be in touch soon.

Best Regards

Kevin Chant
Perth
Western Australia

Re: Philco 89 / 19 transformer (and other bits.) - Radioroslyn - 08-04-2010

Hi Kevin,
Welcome!To the Phorum!
That tone cap or caps wiring isn't very critical. The bottom end can be hooked to ground, the screen grid of the output tube, or the bottom end of the output transformer (at the B+ or HT connection) All will do the same thing. If it is hooked to the SG or transformer you can use a lower voltage rated cap as it won't have all of the B+ on it. On the older Philco sets the tone switch and caps where made together so the frame of the switch would act as the ground connection. The 89 is a great little set and has a rf amp to boot! You may want to have a look at the osc tickler winding. Me thinks that a common problem with that set. There's also a few different versions with different tube line ups.
Terry

Re: Philco 89 / 19 transformer (and other bits.) - Guest - 08-05-2010

G'day Terry, thanks for the info.

The radio is certainly busy underneath, although there was some room freed up during the recapping process. The block components were a novel idea, no real issue once you have the data sheet downloaded from the Philco site. I would hate to think about repairing this radio without the cross reference / component value lists.
I checked the Osc windings and they appear to be continuos, although this oftens changes once power is applied. It appears as though there were a few factory revisions along the way but these should be easy to spot as I work my way through the innards.

I have selected a suitable power tranny, four bolts and a bit of wiring and I hope the old girl will sing again.

I'll keep you updated on progress.

Cheers

Kev.