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Philips 170A

Domestic Valve & Transistor receivers, Radiograms, Gramophones, Amplifiers, Hi-fi, Speakers, Record players, Music centres, Tape machines, Cassette players & Jukeboxes
 
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Philips 170A

Post by sideband » Thu Jul 28, 2011 11:22 pm

I'm working on this set as time permits (never enough of it is there)? All the leaky waxies have been replaced and a good EBL31 was found on eBay. Unfortunately the AZ31 is quite low so in order to get it working something like normally, I temporarily wired in a couple of silicon diodes with limiter resistors. The wiring is in a terrible state with lots of the rubber covered stuff just crumbling and flaking. However I managed to make it safe enough to power up and assess that everything was in pretty good shape.

I've now started on the rewire job. These sets are not the easiest to work on as anyone who has worked on one will know.



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The last picture shows the partly rewired lampholders. I'll start on the transfomer next.... :?

 
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Post by sideband » Fri Jul 29, 2011 9:35 am

This photo actually shows the state the wiring is in. This was taken just before I started to rewire the pilot lamps. The bunch of wires going off to  the valveholder on the bracket are the wires to the tuning indicator. They are taped up with the old cloth type insulating tape which has gone as hard as the rubber insulation and the debris of this can be seen in the last photo in the first post above. I had to 'chew' this off with cutters before I could separate the leads and then more insulation fell off....!

The rubber insulation from the mains socket to the transformer has also started to crack so I'll need to spend an evening or so sorting all this out.

Fortunately most of the wiring underneath or 'below decks' is pretty good so I only need to replace any that has actually failed.

I'll post the progress of this restoration as I go.

Anyone contemplating one of these should certainly do so. They are very good when working and the addition of an RF amplifier really improves performance.
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Post by CTV » Fri Jul 29, 2011 9:59 am

Hi Rich,

Nice set, this as you know this also went under the Mullard badge as the MAS281.

That wiring looks very scary indeed, I had similar poor condition wiring on a TV22 it just crumbled if you looked at it.

Looking forward to the rest of your journey with this set.

Chris

 
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Post by sideband » Sun Jul 31, 2011 6:32 pm

I've done some more rewiring to this over the last few days. It's like a sweatbox up in the loft workshop at the moment so I'm waiting for it to cool a bit and I'll post some more pictures of progress.


SB

 
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Post by CTV » Sun Jul 31, 2011 6:38 pm

sorry to put this image in your head but before I insulated and put in a window, my loft was so hot I would sit in my pants working. Hence a good tip not do so so when soldering, those splashes hurt  :shock:

Chris

 
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Post by sideband » Sun Jul 31, 2011 6:49 pm

I can picture it Chris.....

Insulation is coming but it'll be very much a work-in-progress. I've got a thermocouple on my testmeter at the moment and it's showing 38C.......!

 
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Post by sideband » Sun Jul 31, 2011 11:13 pm

OK back to the 170A. Having donned beachware, I ventured into the loft workshop where the temperature now read 28C. I settled down for a spot more rewiring and completed the pilot lamps and magic eye. Most of the rubber covered wire is yellow so I've gone for a good match PVC alternative. The other two colours are blue and brown which are easy to find and I used some PVC wire stripped from a mains lead. I had previously removed the scale and tuning pointer assembly to give easier access.


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Rewiring one of these can be tricky as a lot of the connections are buried. I find it's better to do small sections at a time, wire for wire, keeping the replacement as close to the routing of the original as possible. Sometimes I only complete a few cable runs at a time, maybe spending an hour or so at a time. It can get very tedious and you have to decide the best way to do it, often deciding what to replace as you go.

The key is to take your time and make a neat job first go. Very often you will find a wire shares a connection with two or three others. A good solder sucker comes in handy here and you can remove the solder and free the connections. Where you have several long wires, it looks very neat if you can thread them through 'collars' of black heat-shrink sleeving. That's what I've done here. Originally the wires were taped together with the old cloth insulation tape which had gone hard. When you've finished the section and all wires are in place, just shrink the sleeving with the hot-air gun and it will all be held in place.

Next I will rewire the rectifier and mains transformer.


SB

 
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Post by CTV » Mon Aug 01, 2011 7:49 am

Hi Rich,

Very neat work it's looking great so far, as you say the heat shrink collars keep it tidy too. With the heat in your loft I expect they close themselves up without need for as gun ;)

Chris

 
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Post by sideband » Mon Aug 01, 2011 10:01 pm

Spent only about 3/4 hour on this tonight mainly due to the time. I decided to rewire the rectifier valve base and this was probably the easiest part so far. I've just got a single earth wire left to do. Pictures show before and after. Once again a single 'collar' of shrink-wrap makes a tidy job and it sits under the cable clamp nicely.

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Next will be the mains wiring from the voltage selector.

SB

 
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Post by sideband » Sun Aug 07, 2011 8:56 pm

Well I've done some more rewiring on this today. I did the output transformer next as there were connections from the rectifer to the output tranny. Some quite long wiring runs so once again I used collars of shrink sleeving to keep it neat. I also rewired the single lead to the top cap of the EBL31 which had also gone hard and brittle.

Next I started on the mains transformer/voltage selector. Fortunately the sub-panel that holds the mains inlet pins can be removed and it makes rewiring simpler. I also gave the mains transformer a good clean which makes it look tidy.

Next I'll do the wiring from the on/off switch to the voltage selector.
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Post by sideband » Thu Aug 11, 2011 11:20 pm

Well I was able to spend a few hours up in the workshop tonight and the wiring above chassis is now complete. This was the wiring between the mains switch and transformer and the mains input connector. The latter is on a paxolin panel in front of the mains transformer and can be removed by undoing two screws which makes access to the mains input pins and voltage selector very easy.

Once again, the fairly long runs of wire between the input socket and mains switch are kept tidy by using heat-shrink collars. I'm quite happy with the end result and have included some pictures. It certainly looks a lot better than it did and will be reliable and safe.

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Once I'd refitted the valves, I tried the set and it worked fine.

The Taylor is showing the emission of the AZ31 and you can see that it is way down...both sections read about the same and it's only giving me about 160V HT instead of 260V. Surprisingly the radio works well at this lower voltage although the output is down and it struggles on SW on the higher frequencies. I'm sourcing a new one.

Next job is to see what needs rewiring under the chassis.


SB

 
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Post by CTV » Fri Aug 12, 2011 9:38 am

Hi Rich,

Looking good and very neat/tidy rewiring. Thanks for posting your restoration log, I always find this style of posting fascinating as Its like looking over the restorers shoulder.

Look forward to more instalments.

Chris

 
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rewireing

Post by rob t » Fri Aug 12, 2011 11:10 am

here is a bit of a short cut i used on an old ekco,here is one of the befor pics Image
what i did was disconect one end of the wire in question pull off the damaged rubber and fit woven 1mm glass fibre sleeve this works well if the wire goes to some ware hard to get at eg the back side of a wave change switch i used it on the ekco because i did not want to damage the vale holders
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rob t

 
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Post by sideband » Fri Aug 12, 2011 11:23 pm

Well last night I completed the wiring above chassis and tonight I was pondering whether to do any under-chassis wiring. I decided I wasn't really in the mood for digging around underneath...some of the wiring is really buried so I'll have to evaluate what really neads doing and what can be left.

That being the case I spent an hour clearing up the workshop whilst the 170A was playing 'Gold' in the background. During the clear-up I found a bag of odd valves, none in boxes. Something told me that I'd picked these up some years ago from a business that had closed and were destined for the skip. I'd forgotten about them and looked inside. One caught my eye straight away and when I looked closely it said 'Philips AZ31'! I couldn't believe it, just what I needed to replace the severely low emission one in the 170A, assuming it was OK of course. A quick check on the Taylor confirmed that both sections were good and very well matched.

It went straight into the 170A and once all the valves had warmed up again, was giving a whopping 264 volts on the reservoir capacitor...104V more than the old one! The HT on the set is now correct and it was louder and more sensitive.

Result!!

Picture of the chassis so far with the newly fitted AZ31 on the left.

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Next I have to tackle the buried perished wiring underneath

 
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Post by CTV » Sat Aug 13, 2011 9:07 am

That chassis is looking very smart now, what a result with the valve too.  Looking forward to the underside work, how is the cabinet?

I always seem to find that no matter how many valves I collect and I have a fair few now, ( nothing compared to our man Luke :shock: ) the set I'm currently working often presents me with the one valve that I do not have in stock  :roll:

Chris

 
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Post by sideband » Sat Aug 13, 2011 11:04 am

Hi Chris. The cabinet is quite good but I'm not sure about the speaker cloth. I'll have to take it out of the box I put it in and look. These are smart-looking sets so if the cloth needs replacing, it needs a sympathetic copy or it won't look right. If it's just slightly frayed, then gentle cleaning with upholstry cleaner is probably best but with cloth of 65 years old, anything done carries a risk of total disintegration (been there done that)!

SB

 
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Post by sideband » Sun Aug 14, 2011 9:45 pm

Tonight I carried out some rewiring under the chassis. I've replaced the worst and the critical (like live leads running close to chassis). I have to say it's a bit of a rats nest underneath...even the original wiring is bent at odd angles and threaded underneath other components, switches and screening plates. There is only a small amount of rubber insulation left now and out of that, I may replace one of the heater runs. The rest is either OK or is non-critical (= unlikely to short against anything else if the rubber should disintegrate). For the moment, I'll leave the chassis as it is and concentrate on cleaning up the cabinet, tuning scale assembly and speaker cloth.


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Sharp eyes may be able to see a radial electrolytic roughly in the centre of the chassis, It's actually mounted on a small tagstrip and it will have to stay there until I can find an old can with a mounting stud and nut to restuff. The originals were missing and a rather untidy double can had been hung in the wiring underneath. I've managed to find one can and restuff it and then fit it in the original place of the reservoir. I need to do the same with the smoothing can.

This slightly closer shot shows the wiring..the brighter yellow is new wire. See what I mean about buried?!

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SB

 
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Post by FRANK.C » Tue Aug 23, 2011 10:49 pm

Hi Rich
What great progress and a very tidy job.
I have one of these and it is a good performer, I was lucky that the wiring was OK.
But I know what it is to rewire a radio as I had a Mullard that the wiring was bad. It was far more time consuming than what I imagined, but was very satisfying when completed.
Looking forward to see it in its cabinet.

Frank

 
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Post by sideband » Thu Aug 25, 2011 6:40 pm

FRANK.C:1665 wrote:But I know what it is to rewire a radio. It was far more time consuming than what I imagined, but was very satisfying when completed.
Frank


Hi Frank. Thanks for the comments....we must be mad doing things like this but if we didn't, a lot of this history would be gone forever.


SB

 
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Post by sideband » Sun Aug 28, 2011 11:36 pm

I was able to spend a couple of hours this evening and I've cleaned up the pilot lamp reflector and refitted the tuning assembly. I've refitted the EM34 tuning indicator and the tuning cursor although as yet the tuning scale and diffuser are not fitted. There are some rubber gaskets fitted each end of the tuning scale and diffuser and typically these have completely disintegrated so I need to find something to replace them with.

The tuning assembly is composed of a number of separate components. There is the scale itself and then behind that is the diffuser. The tuning cursor is mounted on a carrier that slides across the bottom runner and is coupled to the tuning gang by a metal cord. I removed the scale and diffuser and cleaned the rest up 'in situ'. The carrier was sticky with dried grease so this was all cleaned off and light grease reapplied. The tuning scale and diffuser were carefully cleaned and put aside until suitable rubber gaskets can be found (I think thick rubber bands will be suitable). The lamp reflector has also cleaned up well and will not need repainting.

Having cleaned and refitted the tuning assembly (without the scale and diffuser) I've taken some pictures to show the assembly. Philips really went to town on this! The radio is looking much more complete and the new wiring will ensure reliability. The EM34 is rather dim but it is working and can be seen in the last picture (lights out)! It's a little blurred because I had to turn the flash off and use a slow shutter speed.

Next job is to find some flat rubber bands to use a gaskets and refit the diffuser and scale.


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The tuning scale assembly and the pilot light reflector


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The diffuser behind the scale

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The tuning pointer and carriage


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The cleaned up pilot lamp reflector refitted


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The tuning assembly and EM34 refitted

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How it looks from the rear.


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The rather dim EM34.


SB
Last edited by sideband on Sun Aug 28, 2011 11:55 pm, edited 1 time in total.

 
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Post by sideband » Sun Aug 28, 2011 11:54 pm

Whilst I was checking the set again, I was aware of rustling noises that could be cured by tapping the EBL31. It's done ths a few times in the past and I thought it was dirty contacts. This valve had already been changed for a good (supposedly) used sample.

Anyway this time I found that the noise could be made to come and go almost at will by touching the top cap connector. I noticed that the connector was slightly loose. It was gripping the actual valve connector OK but the rivet connecting it to the solder tag was loose. I found the best way to cure this was to run solder all around connector between it and the solder tag. Instant cure, no more rustling noise...I wonder if the original EBL31 will now work OK?


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The top cap connector showing the loose rivet


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The repair.



SB

 
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Post by sideband » Sun Sep 11, 2011 10:11 pm

sideband:2039 wrote:I wonder if the original EBL31 will now work OK?


...yes it does..! I like to keep as many of the original valves in the set as possible so it's only had the reccy replaced. Not bad for 65 years old.


SB

 
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Re: Philips 170A

Post by sideband » Sat Aug 20, 2016 11:55 pm

I didn't realise nearly 5 years had passed since I last posted anything about this set! :ccf

Well it's been sitting by the side of the bench slowly gathering dust but to be fair I have powered it up a couple of times for a few hours. No reason for the stalled restoration other than different sets that come along and take my interest. Anyway electrically the set was completed barring the replacement of a smoothing capacitor with something more in keeping with the original which had been removed at sometime in the past. At the moment I'd temporarily wired in a 47uF on a piece of tagstrip.

A month or so ago I ordered same rather nice 32uF 500V bolt-in caps from Ask Jan First. One went in to my Philips 206A, the other was destined for this 170A and tonight was the night it was finally fitted. Out with the temporary 47uF and in with the new 32uF which fills the vacated hole very nicely. I'd also (last year) fitted a good used EM34 which, although not perfect, presents a very acceptable display.

So now I can say that the electrical work really is finished and all I have to do is replace the torn speaker fabric and then try and remember how it all goes back together.... :aab
Attachments
js640_SAM_0928.jpg
Replacement capacitor bolted in and wired
js640_SAM_0929.jpg
New capacitor fills the vacant hole left by the original with a couple of valves removed for clarity
js640_SAM_0930.jpg
...with the valves refitted
js640_SAM_0932.jpg
Working. The replacement EM34 is quite bright
js640_SAM_0933.jpg
Close up

 
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Re: Philips 170A

Post by crackle » Sun Aug 21, 2016 9:17 am

Its funny how some restorations get put to one side as new and interesting toys come your way, and they just have to be looked at and tested. Then you just have to try "that" to see if that cures a fault, then try "this" and then "something". :qq1

Mike


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