Halli. SX 28 Gearbox.(Part 1) - UK Vintage Radio Repair and Restoration Discussion Forum

ms660 · 25th Jul 2011, 2:55 pm

I thought I would post this as it might be of some use to some one.

The main tuning/clutch on my SX28 has started to stiffen up lately so I decided to whip out the gearbox and see what I could manage.
For those who have fully stripped and put back together one of these boxes you will know how difficult it is and is definately not for the feint hearted.
Once the front panel is removed, removing the gearbox is reasonably straight forward in my case I did not have to worry about the band indicator cord as it had already broken!
With the gearbox out I gave it a good clean and did a pre lube/ degrease to the bearings with WD 40.
I was going to strip the gearbox completely but decided without much persuasion not to bother.
The main stiffness seemed to be around the main tuning shaft and bearings with quite a loud rumble noise when the shaft was spun hard.The main tuning shaft is a concentric affair the outer carries the primary drive gear and logging scale, the inner the flywheel, clutch and main tuning knob.
The outer and inner shaft were binding quite tight so the first job was to remove and clean, so I slackened off the flywheel screws then unscrewed the flywheel and removed it along with the clutch washers then gave the shaft the WD treatment up both ends and left it for an hour after which the inner seperated from the outer by pulling from the front and at the same time turning the inner anti clockwise WRT the outer.
Attention was then turned to the outer shaft, the rear ball bearings are in a housing at the rear of the unit, the housing can be unscrewed once it's locking nut is removed, this was done after putting it face down on a clean white sheet on the bench to catch the inevitable!
I counted thirteen of 'em, some shiny some black and some rusty, these were put in a jar lid and soaked in oil & WD.
Removing these frees up the outer shaft so that the front bearings can be "shaken out" these were in a similar state and were given the same trreatment.
Once removed the rear bearing housing can be cleaned and any sludge removed, the front bearing housing is cleaned in situ using a few good squirts of WD and some tissue, the bearing shoulders on the outer shaft were also cleaned the same way.
I will post part two of this thread in a bit.

Cheers.

ms660 · 25th Jul 2011, 11:53 pm

Part 2:

Next the end bearing adjustment screws on the rest of the shafts where unscrewed by three quarters of a turn after first slackening the lock nuts, this gave enough slack on the shafts to enable a drop of fresh oil to be applied to the ends but without the gears losing mesh, the oil was applied from the inside of the main gearbox plates via a syringe and some thin tubing enough oil then found its way along the ends of the shafts and into the bearings.
The bearing adjusment scews were then tightened up again till they just pinched the shafts then were slackend of by an eigth of a turn.
Next job was to check that the anti backlash gears were working, I usually do this by inserting a thin flat bladed screwdriver across two of the teeth and gently twist the screwdriver, if the gears are ok then the two teeth will move WRT each other and return back when the screwdriver is untwisted. In this case all was OK, the original soaking with WD had done it's stuff. Oil was then applied along the joint of the two faces of the gears and allowed to penitrate then all gear teeth were given a light coating of grease.
Next job was to clean as best as possible the ball bearings that were removed from the main tuning shaft earlier, they had already had a good soak and were given a final clean by rolling them around in oil on a very fine peice of emery paper and then cleaned up.
The front bearing housing was filled with grease and half of the ball bearings that were removed were then inserted using a set of small sniped nose pliers, the outer drive shaft being jammed up to facilitate this operation, more grease was packed in on top and the shaft lowered into position the anti backlash gear was biased and engaged the shaft was kept central whilst turning in order to settle the ball bearings in.
Next was to fit the rear ball bearings, when the front panel of the receiver was removed I had to unscrew a couple of shaft bushes, one of these bushes can be used to help fit the ball bearings back into to the rear housing, I inserted the collar of one of these bushes through the back end of the rear bearing housing then placed them both on a flat surface with the open side of the bearing housing facing upward.
Grease was then packed between the gap now created and the ball bearings were placed around the edge and pessed down very lightly as far as they would go.
Once all the bearings were in, the shaft bush was slowly withdrawn and the ball bearings were pressed down with a blunt plastic knitting needle following the shaft bush as it was withdrawn, the end result was that all the bearings end up in the right place and in a circle and being held in place by the grease.
This assembly was then carefully lowered over the rear of the outer shaft and slowly scewed back into position, then tightned by hand and the lock nut put on but left loose, everything was spun up a few times and all the bearing adjustments carried out and lock nuts tightened. The inner drive shaft was cleaned up and greased then fed through the outer shaft, the clutch washers and flywheel were put back and the flywheel position set to give a nice clutch action.
The whole thing was then spun up again to check everything, the difference all this has made was quite amazing, both the main tuning and bandspread run very light and smooth as a result with only a slight rumble if spun at full speed.

Cheers.

M0FYA Andy · 26th Jul 2011, 7:21 am

Thanks for this detailed description!

Were you not tempted to replace the corroded balls? I admit don't know how easy it is to buy ball bearings loose as opposed to in a complete bearing.

Andy

MichaelR · 26th Jul 2011, 7:27 am

Indeed did you ensure that there were no balls missing. The rumble would indicate wear I guess.

Sterling effort though , it would have been nice to have some pictures. I wonder if this could be kept as a "stickie" for future reference for others.

Mike

ms660 · 26th Jul 2011, 8:24 pm

Thanks for the replies Andy & Mike.

It would have been a pain for me to try and get new ball bearings, time,hassle etc. plus I have not got anything accurate to measure them with, they didn't clean up to bad really. I managed not to loose any (that's a first)
Also there was slight pitting on the bearing shoulders on the shaft and quite a bit inside the rear bearing housing. Despite all that the differance betwen before and after was quite marked, so I am happy with it now considering it's around 70 years old.
The set was working not to bad as far as reception goes but it needs a full re cap. and probably a lot of resistors changing, both 6V6's in the push pull are into grid current due to leaking waxies and I dare say there are others, also some of the wiring needs replacing especialy the heater and mains/ht runs
So it's major surgery! they are not the best of sets to work on.
Having said that I guess most of the Hallicrafters sets were aimed at the Amature/Domestic market and don't have the same build quality as sets that were made for government contracts.
This set is a bit of a labour of love, I have lost count of the number of times it's been on and off the bench, still it's getting clearer now as to what tasks need to be done and what has to be replaced.
I did not take any photo's but I will take some of the front panel once I have refurbed it, but none of the chassis topside as it's abit of a rust bucket! Despite that I am determined to carry out all the repairs I can to get it working up to spec as a fully functioning and usable receiver.
I find it a personal quest too, myself like many others are now the last direct link to those who fought in the last world war so it's imortant to still have equpment from that period still working where it's possible to do so.
I can remember how I felt when a Spitfire was practicing for the Farnborough Air Show when we were constructing one of the exhibition stands.
I had the same feeling last year when I saw a Vulcan bomber fly over our house on it's way to Air Day at RNAS Culdrose.

All the best.

MichaelR · 26th Jul 2011, 9:36 pm

Hi lawrence,

That is the way to tackle the boat anchors a bit at a time if you are not careful it can become an obsession and more like work. It is a hobby for God's sake.

As far as wiring goes I have had 3 HRO's through my hands and every one of them the wiring was as good as the day it was installed . The mains leads looked aged but the mains wiring was still very good. The quality of components orginally used in the US stuff is outstanding. The ony set I think is overrated is the AR88. For the size and looks it promises a lot but for me just does not deliver.

I keep my collection to a minimum and over the years I just keep using them and maintaining them.

The history side does appeal to me and yes it is important to keep memory of how they were used and the importance they and their operators had. The R1155 is not a very good performing set compared to many others but it outshines in relevance for the RAF guys that used it. Keeping some sense to it all though not much stuff even if made in the WW2 era that has survived saw any action but they are working examples and it is about as close as it can be got.

Mike

ms660 · 26th Jul 2011, 10:44 pm

Hello Mike, Funny you should mention the AR88..although I have one I rarely use it for SWL my main beef with it is the lack of a front panel control for fine adjustment of the Xtal filter which I find helpful when trying to resolve some signals, also no bandspread.
Like you say it looks very promising but some how it doesn't seem to have the edge.
My work on these old sets is begining to take over a bit! Mainly because I need to get them done and dusted as I have a stack of other things to do (house etc)
I seem to remember you saying once that you had a full WS 19 set up, do you have the same for the R1155 ?
I read the Hammarlund section in the link you posted, very interesting, the author of that website has done some great work there.

Lawrence.

MichaelR · 27th Jul 2011, 8:24 am

Hi Lawrence,

For the R1155 I have a completely working unit with everything as it should be ( D/F section etc). I do not have an authentic ground station PSU , I have been hoping to get one for sometime but when they come along they are asking silly money.

There is a guy on the internet who has produced a seperate D/F unit with the built in swing needle meter, I now have one of these original meters so I intend to build that.

I would have liked to get a T1154 and run them together but again the prices are just ludicrous, I will leave that to others.

My next project for winter is to get a TCS12 receiver/transmitter up and running. I have had these units for about 4 years awaiting something to be done , again I brought them in from the States and they are complete and unmodified. I need to build a power supply for them.

Regards
Mike

ms660 · 27th Jul 2011, 5:57 pm

Hello Mike...yes the T1154 seem to fetch very high prices, I think the last one I saw on 'tinternet was around 600 quid mark (I wonder if it's the colour coded knobs!) I watched a program the other night on BBC4 about the old 60's rockbands and in the room that one of them was being interviewed was a T1154 built into the wall, wether he was a keen radio bloke I've no idea.
Well you certainly seem to have quite a collection there Mike, you must have taken a lot of time, effort and thought to assemble working station set ups etc.
The Collins project will be interesting and very worth while me thinks.
It's no good I will have to send off to the States for something! I would dearly love an early Collins or any Collins in fact.
It's just a case of taking the plunge..he who hesitates is lost..as they say.
Keep up the good work.

Lawrence.

25th Jul 2011, 2:55 pm	#1
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Halli. SX 28 Gearbox.(Part 1) I thought I would post this as it might be of some use to some one. The main tuning/clutch on my SX28 has started to stiffen up lately so I decided to whip out the gearbox and see what I could manage. For those who have fully stripped and put back together one of these boxes you will know how difficult it is and is definately not for the feint hearted. Once the front panel is removed, removing the gearbox is reasonably straight forward in my case I did not have to worry about the band indicator cord as it had already broken! With the gearbox out I gave it a good clean and did a pre lube/ degrease to the bearings with WD 40. I was going to strip the gearbox completely but decided without much persuasion not to bother. The main stiffness seemed to be around the main tuning shaft and bearings with quite a loud rumble noise when the shaft was spun hard.The main tuning shaft is a concentric affair the outer carries the primary drive gear and logging scale, the inner the flywheel, clutch and main tuning knob. The outer and inner shaft were binding quite tight so the first job was to remove and clean, so I slackened off the flywheel screws then unscrewed the flywheel and removed it along with the clutch washers then gave the shaft the WD treatment up both ends and left it for an hour after which the inner seperated from the outer by pulling from the front and at the same time turning the inner anti clockwise WRT the outer. Attention was then turned to the outer shaft, the rear ball bearings are in a housing at the rear of the unit, the housing can be unscrewed once it's locking nut is removed, this was done after putting it face down on a clean white sheet on the bench to catch the inevitable! I counted thirteen of 'em, some shiny some black and some rusty, these were put in a jar lid and soaked in oil & WD. Removing these frees up the outer shaft so that the front bearings can be "shaken out" these were in a similar state and were given the same trreatment. Once removed the rear bearing housing can be cleaned and any sludge removed, the front bearing housing is cleaned in situ using a few good squirts of WD and some tissue, the bearing shoulders on the outer shaft were also cleaned the same way. I will post part two of this thread in a bit. Cheers.

25th Jul 2011, 11:53 pm	#2
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Halli. SX 28 Gearbox.(Part 1) Part 2: Next the end bearing adjustment screws on the rest of the shafts where unscrewed by three quarters of a turn after first slackening the lock nuts, this gave enough slack on the shafts to enable a drop of fresh oil to be applied to the ends but without the gears losing mesh, the oil was applied from the inside of the main gearbox plates via a syringe and some thin tubing enough oil then found its way along the ends of the shafts and into the bearings. The bearing adjusment scews were then tightened up again till they just pinched the shafts then were slackend of by an eigth of a turn. Next job was to check that the anti backlash gears were working, I usually do this by inserting a thin flat bladed screwdriver across two of the teeth and gently twist the screwdriver, if the gears are ok then the two teeth will move WRT each other and return back when the screwdriver is untwisted. In this case all was OK, the original soaking with WD had done it's stuff. Oil was then applied along the joint of the two faces of the gears and allowed to penitrate then all gear teeth were given a light coating of grease. Next job was to clean as best as possible the ball bearings that were removed from the main tuning shaft earlier, they had already had a good soak and were given a final clean by rolling them around in oil on a very fine peice of emery paper and then cleaned up. The front bearing housing was filled with grease and half of the ball bearings that were removed were then inserted using a set of small sniped nose pliers, the outer drive shaft being jammed up to facilitate this operation, more grease was packed in on top and the shaft lowered into position the anti backlash gear was biased and engaged the shaft was kept central whilst turning in order to settle the ball bearings in. Next was to fit the rear ball bearings, when the front panel of the receiver was removed I had to unscrew a couple of shaft bushes, one of these bushes can be used to help fit the ball bearings back into to the rear housing, I inserted the collar of one of these bushes through the back end of the rear bearing housing then placed them both on a flat surface with the open side of the bearing housing facing upward. Grease was then packed between the gap now created and the ball bearings were placed around the edge and pessed down very lightly as far as they would go. Once all the bearings were in, the shaft bush was slowly withdrawn and the ball bearings were pressed down with a blunt plastic knitting needle following the shaft bush as it was withdrawn, the end result was that all the bearings end up in the right place and in a circle and being held in place by the grease. This assembly was then carefully lowered over the rear of the outer shaft and slowly scewed back into position, then tightned by hand and the lock nut put on but left loose, everything was spun up a few times and all the bearing adjustments carried out and lock nuts tightened. The inner drive shaft was cleaned up and greased then fed through the outer shaft, the clutch washers and flywheel were put back and the flywheel position set to give a nice clutch action. The whole thing was then spun up again to check everything, the difference all this has made was quite amazing, both the main tuning and bandspread run very light and smooth as a result with only a slight rumble if spun at full speed. Cheers.

26th Jul 2011, 7:21 am	#3
M0FYA Andy Nonode Join Date: May 2007 Location: Preston, Lancashire, UK. Posts: 2,511	Re: Halli. SX 28 Gearbox.(Part 1) Thanks for this detailed description! Were you not tempted to replace the corroded balls? I admit don't know how easy it is to buy ball bearings loose as opposed to in a complete bearing. Andy

26th Jul 2011, 7:27 am	#4
MichaelR Retired Dormant Member Join Date: Mar 2006 Location: Sheffield, South Yorkshire, UK. Posts: 1,587	Re: Halli. SX 28 Gearbox.(Part 1) Indeed did you ensure that there were no balls missing. The rumble would indicate wear I guess. Sterling effort though , it would have been nice to have some pictures. I wonder if this could be kept as a "stickie" for future reference for others. Mike

26th Jul 2011, 8:24 pm	#5
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Halli. SX 28 Gearbox.(Part 1) Thanks for the replies Andy & Mike. It would have been a pain for me to try and get new ball bearings, time,hassle etc. plus I have not got anything accurate to measure them with, they didn't clean up to bad really. I managed not to loose any (that's a first) Also there was slight pitting on the bearing shoulders on the shaft and quite a bit inside the rear bearing housing. Despite all that the differance betwen before and after was quite marked, so I am happy with it now considering it's around 70 years old. The set was working not to bad as far as reception goes but it needs a full re cap. and probably a lot of resistors changing, both 6V6's in the push pull are into grid current due to leaking waxies and I dare say there are others, also some of the wiring needs replacing especialy the heater and mains/ht runs So it's major surgery! they are not the best of sets to work on. Having said that I guess most of the Hallicrafters sets were aimed at the Amature/Domestic market and don't have the same build quality as sets that were made for government contracts. This set is a bit of a labour of love, I have lost count of the number of times it's been on and off the bench, still it's getting clearer now as to what tasks need to be done and what has to be replaced. I did not take any photo's but I will take some of the front panel once I have refurbed it, but none of the chassis topside as it's abit of a rust bucket! Despite that I am determined to carry out all the repairs I can to get it working up to spec as a fully functioning and usable receiver. I find it a personal quest too, myself like many others are now the last direct link to those who fought in the last world war so it's imortant to still have equpment from that period still working where it's possible to do so. I can remember how I felt when a Spitfire was practicing for the Farnborough Air Show when we were constructing one of the exhibition stands. I had the same feeling last year when I saw a Vulcan bomber fly over our house on it's way to Air Day at RNAS Culdrose. All the best.

26th Jul 2011, 9:36 pm	#6
MichaelR Retired Dormant Member Join Date: Mar 2006 Location: Sheffield, South Yorkshire, UK. Posts: 1,587	Re: Halli. SX 28 Gearbox.(Part 1) Hi lawrence, That is the way to tackle the boat anchors a bit at a time if you are not careful it can become an obsession and more like work. It is a hobby for God's sake. As far as wiring goes I have had 3 HRO's through my hands and every one of them the wiring was as good as the day it was installed . The mains leads looked aged but the mains wiring was still very good. The quality of components orginally used in the US stuff is outstanding. The ony set I think is overrated is the AR88. For the size and looks it promises a lot but for me just does not deliver. I keep my collection to a minimum and over the years I just keep using them and maintaining them. The history side does appeal to me and yes it is important to keep memory of how they were used and the importance they and their operators had. The R1155 is not a very good performing set compared to many others but it outshines in relevance for the RAF guys that used it. Keeping some sense to it all though not much stuff even if made in the WW2 era that has survived saw any action but they are working examples and it is about as close as it can be got. Mike Last edited by MichaelR; 26th Jul 2011 at 9:38 pm. Reason: grammar

26th Jul 2011, 10:44 pm	#7
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Halli. SX 28 Gearbox.(Part 1) Hello Mike, Funny you should mention the AR88..although I have one I rarely use it for SWL my main beef with it is the lack of a front panel control for fine adjustment of the Xtal filter which I find helpful when trying to resolve some signals, also no bandspread. Like you say it looks very promising but some how it doesn't seem to have the edge. My work on these old sets is begining to take over a bit! Mainly because I need to get them done and dusted as I have a stack of other things to do (house etc) I seem to remember you saying once that you had a full WS 19 set up, do you have the same for the R1155 ? I read the Hammarlund section in the link you posted, very interesting, the author of that website has done some great work there. Lawrence.

27th Jul 2011, 8:24 am	#8
MichaelR Retired Dormant Member Join Date: Mar 2006 Location: Sheffield, South Yorkshire, UK. Posts: 1,587	Re: Halli. SX 28 Gearbox.(Part 1) Hi Lawrence, For the R1155 I have a completely working unit with everything as it should be ( D/F section etc). I do not have an authentic ground station PSU , I have been hoping to get one for sometime but when they come along they are asking silly money. There is a guy on the internet who has produced a seperate D/F unit with the built in swing needle meter, I now have one of these original meters so I intend to build that. I would have liked to get a T1154 and run them together but again the prices are just ludicrous, I will leave that to others. My next project for winter is to get a TCS12 receiver/transmitter up and running. I have had these units for about 4 years awaiting something to be done , again I brought them in from the States and they are complete and unmodified. I need to build a power supply for them. Regards Mike

27th Jul 2011, 5:57 pm	#9
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Halli. SX 28 Gearbox.(Part 1) Hello Mike...yes the T1154 seem to fetch very high prices, I think the last one I saw on 'tinternet was around 600 quid mark (I wonder if it's the colour coded knobs!) I watched a program the other night on BBC4 about the old 60's rockbands and in the room that one of them was being interviewed was a T1154 built into the wall, wether he was a keen radio bloke I've no idea. Well you certainly seem to have quite a collection there Mike, you must have taken a lot of time, effort and thought to assemble working station set ups etc. The Collins project will be interesting and very worth while me thinks. It's no good I will have to send off to the States for something! I would dearly love an early Collins or any Collins in fact. It's just a case of taking the plunge..he who hesitates is lost..as they say. Keep up the good work. Lawrence.