Cx701 lathe report

[Steamchick]

Thanks Paul. And I had been taught it was "smoke leaking out" that caused all the electronics to stop working. Maybe the gel is condensed smoke? I have seen sticky stuff that has bled from dry cells when they have died... but not from capacitors.
The 2 types of capacitors made in a factory where I worked as a young engineer were high voltage types for phase correction on long overhead power lines, that used paper and oil insulation with aluminium foil plates, and the other sort used polymer insulation and foil wrapped in aluminium cans for fluorescent lamp-ballast inductive compensation. None of these were filled with smoke, so I assumed it was diodes and transistors full of smoke that could leak and fail. I have had a good few of those in devices I have owned. Especially thryristors. They can get quite hot when the smoke leaks out of them....
K2

 

[Richard Hed]

Thanks Paul. And I had been taught it was "smoke leaking out" that caused all the electronics to stop working. Maybe the gel is condensed smoke? I have seen sticky stuff that has bled from dry cells when they have died... but not from capacitors.
The 2 types of capacitors made in a factory where I worked as a young engineer were high voltage types for phase correction on long overhead power lines, that used paper and oil insulation with aluminium foil plates, and the other sort used polymer insulation and foil wrapped in aluminium cans for fluorescent lamp-ballast inductive compensation. None of these were filled with smoke, so I assumed it was diodes and transistors full of smoke that could leak and fail. I have had a good few of those in devices I have owned. Especially thryristors. They can get quite hot when the smoke leaks out of them....
K2

My experience with caps is that they rarely fail unless they are made in China which then, you would not have any idea how good or bad they are. I have had three fail in the Philippines where the culture is: Oh, this *item* will do whatever you want, including stand on it's head, fly to the moon, do germ culture, is halal, kosher and acceptable to Bhuddist dietary law, and many other things. It's as if people of the educated west are totally stupid and ignorant. In America, I thimpfk I have NEVER had a cap fail. However, I repaired one old radio from the 30's that needed new caps.

 

[goldstar31]

As I said, I added a mill drill assembly to my Sieg C4- a Chinese 8 x16 and the mother board failed on the initial switch on. True, it was replaced under warrantee--- but it failed on switch on.
I can only assume that the quality controller -- wasn't.

As most will appreciate, the foregoing was my action as best as I was able NOT to alienate my rights under the appropriate sale of goods acts appropriate to the United KIngdom.
What the law decrees in other countries must wisely be regarded as 'unknown'

 

[Linz]

Earlier today I bench tested the new replacement control board prior to installing on the 701. I used the old VSC pot which tested good on the meter and performed properly with the new board. So, as expected, it was the control board that was faulty on the new machine. The DC output on the new board arrived set to the max of 130volts so I dialed it back to 90VDC via the Max trim pot. Incidentally, I think this trim pot may have been the culprit on the failed board.

Originally, my machine was not wired as per the manual schematic or the hand drawn one that I received from the BusyBee tech. I used a composite of the 3 as I saw best fit the requirements. After re-installing all the electrics in the machine the lathe is now up and running, at least free spinning with no load. It won't be until next week that I can reassemble, the carriage and tailstock parts that were removed for an initial cleaning, and perform the chuck run-out and headstock/tailstock alignment procedures.

 

[Paul135]

Earlier today I bench tested the new replacement control board prior to installing on the 701. I used the old VSC pot which tested good on the meter and performed properly with the new board. So, as expected, it was the control board that was faulty on the new machine. The DC output on the new board arrived set to the max of 130volts so I dialed it back to 90VDC via the Max trim pot. Incidentally, I think this trim pot may have been the culprit on the failed board.

Originally, my machine was not wired as per the manual schematic or the hand drawn one that I received from the BusyBee tech. I used a composite of the 3 as I saw best fit the requirements. After re-installing all the electrics in the machine the lathe is now up and running, at least free spinning with no load. It won't be until next week that I can reassemble, the carriage and tailstock parts that were removed for an initial cleaning, and perform the chuck run-out and headstock/tailstock alignment procedures.

Congratulations on getting the lathe running. Can you confirm please which board you got sent as the replacement? Is it a genuine KB electronics board? I ask from the point of view that there will be other CX lathe users reading this thread. My own experience of the KB board, which I replaced a Chinese copy with has been good. Have you got the additional KB heat sink that this board can be bolted to? If not this could be a good mod to do to further prolong the life of the board. I believe from various internet reports that in the UK the Warco lathes use this board as well and these lathes are normally reported as very reliable.

When you have done your reassembly, could you post your findings please on run-out and alignment?

Paul

 

[Steamchick]

My 1976 Philips tape deck regularly failed the Caps... and my Philips TV is on the 3rd or 4th Power supply - as their caps fail after 5 years or so.... I even bought some caps to do it myself - until I looked indie and didn't know where to start! Otherwise, no problems.
But my speed control on the lathe should be 110rpm to 1250 rpm...it is actually 70 rpm to 1650 rpm - but makes a LOUD "sputtering" noise above 1200 rpm!! - it sounds like major flash-over... but no smoke, so what could be happening? It has blown a few fuses on the mains (13A) and internally (10A - fast blow? - or maybe slow-blow - for the motor?), hardly ever on-load. The start-stop buttons went O-C, so I replaced the unit - with a cheap (£3) Chinese unit that was the only available option. But the variable speed still hasn't lost all its "electronic smoke" though I am sure it must be getting close to empty... by now. Do I buy a replacement board before all the smoke leaks away? - Maybe that would be a good idea... But where to get a good board, not a Chinese board? £70 for a complete Chinese VFD unit that would do the job - but need to re-wire the lathe.
K2

 

[Paul135]

My 1976 Philips tape deck regularly failed the Caps... and my Philips TV is on the 3rd or 4th Power supply - as their caps fail after 5 years or so.... I even bought some caps to do it myself - until I looked indie and didn't know where to start! Otherwise, no problems.
But my speed control on the lathe should be 110rpm to 1250 rpm...it is actually 70 rpm to 1650 rpm - but makes a LOUD "sputtering" noise above 1200 rpm!! - it sounds like major flash-over... but no smoke, so what could be happening? It has blown a few fuses on the mains (13A) and internally (10A - fast blow? - or maybe slow-blow - for the motor?), hardly ever on-load. The start-stop buttons went O-C, so I replaced the unit - with a cheap (£3) Chinese unit that was the only available option. But the variable speed still hasn't lost all its "electronic smoke" though I am sure it must be getting close to empty... by now. Do I buy a replacement board before all the smoke leaks away? - Maybe that would be a good idea... But where to get a good board, not a Chinese board? £70 for a complete Chinese VFD unit that would do the job - but need to re-wire the lathe.
K2

Hi K2, are you sure it is the board and not the brushes on the motor? For a new board have a look here:
https://www.axiscontrols.co.uk/prod...bic-range/kbic-240d-dc-motor-speed-controllerI bought the KB board for my lathe there, very fast delivery. KB if I remember right are in Florida and the boards are supposed to be made in the USA. They are well made in any case. I would recommend the auxiliary heat sink KB offer.

Paul

 

[trlvn]

The replacement control board for my new 701 has arrived so with any luck I might see it spin by days' end.

Was there any charge to you for the board or shipping or was it completely covered under warranty? What shipping method did they use?

Craig

 

[Courierdog]

I worked on High Power Transmitters and many of the high voltage capacitors had a very toxic oil in them. You did not want to be around when one developed a leak or worse when one exploded. Getting a dose of the oil in a gas state was fatal. I had to pull on a person when it happened and please note all these capacitors were made here in North America, no import equipment was used in these old Transmitters, 50 Kw or better, In Canada we had to cut the power back to 50KW as that is our maximum allowable power output.
I dropped a screw driver once, it fell into the high voltage cage, there was a bright light for about three seconds then total darkness. oops
No evidence was ever discovered, and yes 2 seconds later the capacitor bank recovered and the lights came back on.

 

[Richard Hed]

I worked on High Power Transmitters and many of the high voltage capacitors had a very toxic oil in them. You did not want to be around when one developed a leak or worse when one exploded. Getting a dose of the oil in a gas state was fatal. I had to pull on a person when it happened and please note all these capacitors were made here in North America, no import equipment was used in these old Transmitters, 50 Kw or better, In Canada we had to cut the power back to 50KW as that is our maximum allowable power output.
I dropped a screw driver once, it fell into the high voltage cage, there was a bright light for about three seconds then total darkness. oops
No evidence was ever discovered, and yes 2 seconds later the capacitor bank recovered and the lights came back on.

A town I lived in once had a kat get into a powerstation, the only thing left fo the cat was fur. The lights were off for 4-5 hours while something was being repaired. I'm surpized you didn't go blind from looking at that bright light.

 

[BaronJ]

My 1976 Philips tape deck regularly failed the Caps... and my Philips TV is on the 3rd or 4th Power supply - as their caps fail after 5 years or so.... I even bought some caps to do it myself - until I looked indie and didn't know where to start! Otherwise, no problems.
But my speed control on the lathe should be 110rpm to 1250 rpm...it is actually 70 rpm to 1650 rpm - but makes a LOUD "sputtering" noise above 1200 rpm!! - it sounds like major flash-over... but no smoke, so what could be happening? It has blown a few fuses on the mains (13A) and internally (10A - fast blow? - or maybe slow-blow - for the motor?), hardly ever on-load. The start-stop buttons went O-C, so I replaced the unit - with a cheap (£3) Chinese unit that was the only available option. But the variable speed still hasn't lost all its "electronic smoke" though I am sure it must be getting close to empty... by now. Do I buy a replacement board before all the smoke leaks away? - Maybe that would be a good idea... But where to get a good board, not a Chinese board? £70 for a complete Chinese VFD unit that would do the job - but need to re-wire the lathe.
K2

Hi Ken,

Look closely at the motor brushes ! They are a very common source of problems with failed motors and particularly control boards.

 

[BaronJ]

I worked on High Power Transmitters and many of the high voltage capacitors had a very toxic oil in them. You did not want to be around when one developed a leak or worse when one exploded. Getting a dose of the oil in a gas state was fatal. I had to pull on a person when it happened and please note all these capacitors were made here in North America, no import equipment was used in these old Transmitters, 50 Kw or better, In Canada we had to cut the power back to 50KW as that is our maximum allowable power output.
I dropped a screw driver once, it fell into the high voltage cage, there was a bright light for about three seconds then total darkness. oops
No evidence was ever discovered, and yes 2 seconds later the capacitor bank recovered and the lights came back on.

Yes, I'm vary aware of the "Poly Chlorinated Biphenol's" in those oil filled capacitors. You cannot burn them or remove the oil, you cannot bury them unless you enclose them in concrete.

 

[Steamchick]

Thanks Baron. I contacted the "shop" (Industrial unit with no-one home during the pandemic) and a helpful engineer told me how to easily get the motor out and check the brushes. I have ordered new ones. Upon examination I reckon the routing of the brush wire is such that it "holds" the brush against spring pressure, when the brush is about half-worn (30mm => 13mm). A simple tweak of that wire and the brush developed "full pressure" on the commutator - but I can wait and fit the new brushes - with wire situated to use all the brush - then maybe when I am dead and burned someone else can spend a "quick few minutes" (2 hours) fitting new brushes.
It took me a lot longer than expected because the lathes have a long cable so the motor can be removed without disconnecting the wires, yet an Earth wire (compulsory in Europe and UK - not China) - added by the UK importer from the look of it - was too short to get the motor out. So I squeezed a pair of wire cutters in the gap and cut the wire, then spent a happy hour trying to get 2 hands and a soldering iron into a blind hole to join on a longer earth wire... So the "Chinese" bit was OK - The UK addition not so....
Ho hum. It's fixed now. Come on Postman - I want my new brushes!
Next question: To avoid dismantling the motor for cleaning brushes, is it OK to wash away surplus carbon with aerosol Brake cleaner? (Trichloro-whatever is safe enough to sell!)? Looks like a good idea, but maybe it will de-grease the bearings?
K2

 

[ShopShoe]

Here in the USA, the manufacturers of the brake cleaner also make an automotive electrical cleaner for cleaning starters, alternators, etc. for service. I haven't bought any for a few years and I don't know if it's still available or what's in it. Maybe there is a similar product available where you are. There's also the "contact cleaner" from electronics suppliers.

--ShopShoe

 

[BaronJ]

Hi Guys,

I've never used any solvents in the manner that you describe ! The most I've ever done is to blow the motor clean with air. I've skimmed commutators that have been solid with carbon dust and undercut the mica. Not an easy job and very messy.

Personally I wouldn't use them.

 

[Steamchick]

Thanks, I carefully blew some loose dust away... the commutator was pretty clean - but I know carbon dust is a great one for starting a flash-over. Commutators are essentially low speed devices - which we use on high-speed motors... which is why we smell Ozone from them when arcing begins. I wonder if the controller is trying to shut-off every time the commutator flashes over (Instant current surge - no back-emf!) as if it is delivering DC to the motor instead of AC then there is no "zero-point" to break an arc. I don't know what is happening there - just worked on H-V circuit breakers for 4 years as an Engineer - so understand a tiny bit about arc destruction in AC inductive circuits. Commutators are not designed for arc destruction... more like arc propagation, the faster they go!
The motor runs OK with new brushes, but I have lost the drive belt... Don't ask how - I blame the gremlins... Maybe the new brushes have made the Gemlins homeless in the motor, so they have stolen the drive belt and hidden it in revenge? 10 minutes fitting brushes, 10 minutes fitting the motor back onto the lathe - and 2 hours scouring the garage for the drive belt.... Is this Insanity? Senility? just simple stupidity? - just daily life for me....
It is going to spoil my Sunday if it doesn't turn up today.
Cheers guys!
"Have a nice day"
K2

 

[BaronJ]

Hi Guys,

Yes I do tricks like that ! Put stuff in that safe place so that I know where it is, but where was the safe place !!!

The belt is in the same place that you moved it to Evil Gremlins.

 

[Shopgeezer]

The drive belt is wherever you picked something else up. It’s the packrat syndrome, you drop what you are carrying to pick something else up. I once tore the house and shop apart looking for a bearing housing that completely disappeared. I found it in the refrigerator.

 

[awake]

The drive belt is wherever you picked something else up. It’s the packrat syndrome, you drop what you are carrying to pick something else up. I once tore the house and shop apart looking for a bearing housing that completely disappeared. I found it in the refrigerator.

That makes perfect sense - you were heating the casing that the bearing would go into while you were chilling the bearing, right?

 

[Shopgeezer]

Yes that’s my story. Actually I put it down when I got a beer out of the fridge.