MadModder
The Shop => Tools => Topic started by: steampunkpete on December 30, 2014, 03:22:00 AM
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I've acquired a nearly new Clarke C3 mini lathe that was abandoned by its owner because the controller board failed and Clarke wanted £160 for a replacement (the guy had tried to fix it himself and so voided the warranty).
I can either use it for spares or fit a new controller board and sell it on. Taking a £160 hit on the board is not very attractive, but there is a £27 controller on Ebay that might do the job:
http://www.ebay.co.uk/itm/181473818094?_trksid=p2060778.m1438.l2648&ssPageName=STRK%3AMEBIDX%3AIT
It has the right input voltage, but its output is 0V to 220V DC. I could deal with this by adding a ballast resistor to the speed control potentiometer to limit the unit's output voltage to 180V DC.
Has anybody used these before?
Presumably for a permanent magnet motor one would leave the field excitation output unconnected as seems to be the case with other, similar drivers?
Help and suggestions gratefully received.
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I've used one and sold it on.....
The best by far for a controller is the KB board sold by Amadeal.....£85 new iirc...
The KB boards have a number of adjustments to control acceleration, torque and current limiting...
I have several of these boards as a spare for my Chester mill and haven't had to use one yet(except when I helped someone sort their ailing mill out that had a busted controller...)
One thing to remember, any board other than the original will probably need mods to the wiring especially the potentiometer....it's interlocked with the safety features to prevent startup after power failure...
Shout up if you need help... :zap:
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Thanks John,
The fact that you stopped using it and bought the Amadeal board suggests that the Ebay control board wasn't as good. Was there a serious issue with using it?
Pete
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I have one here, bought for a Emco mill but it just blows the internal fuse when it starts.
Not saying the unit is no good as the plate is missing of the Emco so don't know what amperage it needs and I strongly suspect that it needs greater than 4 amps.
Fitted a KB to the Emco and all was well. Kept to Chinese one as a spare for something else. Probably do a C3 OK as it's a far smaller motor than the Emco one but cannot say for definite.
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The standard KB offering is rated for 6 amps with the appropriate hp resistor....
The resistor is used in conjunction with the Current Adj preset.
If the resistor value is incorrect and/or the preset is not set correctly the board will not work as it should.....
The KB manual explains all of this in detail.
I bought the Ebay offering for some other use other than the mill, but wasn't happy with its performance after a technical evaluation....errr didn't buy a board from Amadeal, got them elsewhere...I suggested that Amadeal may be a solution for you, but you may need the KB manual if you go that route as the board does need a bit of setting up.......(I have a copy of the manual if you decide to go that way....) the settings are nothing frightening as long as you can use a Dvm....
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Thanks John,
That would be great. I will try the cheapo ebay thing first, and if I'm not happy to pass it on I'll go the Amadeal route. If you have an electronic copy of the Amadeal controller that would be appreciated as I can store it away in my "just in case" folder.
DVM? I must get one. I usually rely on my trusty AVO 8. Just before I retired I mentioned using an AVO to a spotty youth when explaining something; he asked me what an AVO was - times change (and he didn't know what I meant by "Radio Spares" either; I know it's been called RS for yonks, but old habits die hard).
Regards
Pete
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Hi Pete,
You hang on to the AVO ! I have both AVO 7 and a pair of 8's. One over 40 years old. Digital meters are OK for some jobs, but there are many jobs where an analog meter can't be beaten.
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Pete,
As per the mini mill thread....I'll offer to repair the controller for you...( :zap: :zap:).drop me a pm if you want.
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I have now taken delivery of the lathe. The SoP is as follows:
The lathe is virtually unused - it even has much of the red waxy preservative still on it. My suspicion is that it was in the hands of a beginner who abused it and blew the board first time of use; either that or he was just unlucky.
The accessories were missing - but I knew that.
The drip tray has been bent. I hadn't noticed that, but it is trivial.
I have reconnected the control board after having made one minor modification. The motor leads are fitted with female spade connectors, and these are pushed onto solder tabs on the "Forward-Off-Reverse" switch. This is a horrid bodge that doesn't work at all well, so I've soldered short flying leads onto the switch with female bullet connectors and fitted male bullets to the motor lead.
The symptoms:
A faint crackling sound when applying mains power.
The motor either fails to run and the "Fault" light illuminates.
OR
The motor runs at a constant speed regardless of the position of the speed controller. I would estimate that it is running at about half full speed.
THEN
I disconnected the motor and mains leads prior to removing the control board for the purposes of changing the output drivers.
I wanted to check something and reconnected the mains and motor. One of the mains spade connectors felt a bit dodgy so I tweaked it a bit.
Plugged back into mains, and LO! a miracle had occurred - no crackling noise and it works perfectly.
I'm going to carefully inspect the underside of the controller board for dodgy solder joints just in case, but otherwise I now seem to have another nearly new working mini-lathe. :ddb:
The question now is whether to sell to fund other things, or keep as a spare / for parts.
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Good spot on the dodgy connections......
The board is one of the earlier controllers as fitted...now superceeded by a later version...
But it works! V. Important
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Great good luck on that one, Pete! :thumbup: :clap:
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:offtopic:
Separated again by a common language! I have heard of an AVO forever and always thought it was a brand name. I had to see DVM and AVO in the same sentence to realize that the item was a VOM! Live and learn. :doh:
Joe
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Avo is actually a brand name over here......despite AmpsVoltsOhms..... :lol:
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it is a brand name
still have a MK 8
http://en.wikipedia.org/wiki/Avometer
Stuart
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I have heard of an AVO forever and always thought it was a brand name
AVO is / was indeed a brand name. For oldies like me an AVO will forever be a moving coil instrument in a big black phenolic enclosure made by AVO Ltd (although the company had other names during its lifetime (See http://en.wikipedia.org/wiki/Megger_Group_Limited#AVO).
AVO was absorbed at some point into "Megger" and they now make digital multimeters. With a nod to the past the model numbers start AVO(and then a 3 digit .number).
According to the wiki, AVO originally stood for Amps, Volts, Ohms.
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When I was at school in the mid 1960's the father of a friend was a director of Avo. With only a bit of pushing I managed to wangle a trip round their 'factory' as was on Vauxhall Bridge Road in Victoria. It was actually a sequence of Victorian and Edwardian houses and shops that had been 'knocked though' with little odd corners doing fragments of the largely hand manufacture. Numerous 'Douglas Coil Winders' (Douglas being owned by Avo) producing coils for the Avo's and also various Signal Generators and other test equipment. The smell of shellac pervaded the place.
Soon after that they moved to Dover (Avocet House!) as they combined with Megger.
My meter of choice is still an Avo 8 Mk6 which is always out and at the ready - the DVM only coming out rarely.
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Hi there, Baron,
Hi Pete,
You hang on to the AVO ! I have both AVO 7 and a pair of 8's. One over 40 years old. Digital meters are OK for some jobs, but there are many jobs where an analog meter can't be beaten.
:offtopic:
How do you cope with the 15 volt dry battery problem (for the high Ohms range)? Years ago, I saw a press review of a DC to DC converter that produced the 15 volts from the 1½ volt battery but it never seemed to catch on. Also, I never did work out how you switched it on.
By the way, my Senior Engineer mentor when I was a junior engineer used to emphasise that the Avo 8 is more sensitive than the Avo 7 (lower movement FSD) but the Avo 7 is more precise than the Avo 8 because the Avo 7 uses wirewound resistors while the Avo 8 uses carbon or metal film resistors!
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But you only need the 15v for the high ohms ranges where a dvm is probably better, anyway loads of batteries about if you need them:
http://www.ebay.co.uk/itm/BLR154-BATTERY-FOR-AVO-METERS-15V-504-Multimeter-Alkaline-/400435143828?pt=UK_ConsumerElectronics_Batteries_SM&hash=item5d3bcb6494
http://www.ebay.co.uk/itm/AVO-8-METER-MULTIMETER-15v-BATTERY-BLR-121-AVOMETER-/271712553197?pt=UK_ConsumerElectronics_Batteries_SM&hash=item3f435488ed
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Thanks Andrew,
I looked on ebay years ago, no luck, and didn't think to check again, and I couldn't find any from any other source. I've been making do with two 9-Volt batteries taped together and adjusting out. I know where to get the right one now.
Thanks again,
Pete
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You're very welcome lots about, here's another:
http://www.brewstersbatteries.co.uk/catalog/blr154-gp220-15v-avo-battery-p-393.html?zenid=8e585daa5fefef066b40de12b15d7d0f
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:offtopic:
Separated again by a common language! I have heard of an AVO forever and always thought it was a brand name. I had to see DVM and AVO in the same sentence to realize that the item was a VOM! Live and learn. :doh:
Joe
Hi Joe,
Yes, the AVO which stands for "Amps, Volts, Ohms" became the brand name for the multimeter that for more than 60 years was the industry standard. The "Model 7" was aimed at the electrical market and the "Model 8" was aimed at the wireless/TV/electronics market. It's accurate 20K opv and mirrored scale set it apart from anything else.
There were variations of course, the AVO Minor, a pocket sized version, and the Model 8 with its seven or eight variants. All superb instruments, unfortunately no longer in production. In fact I don't think AVO as a company exist any more.
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:offtopic:
Separated again by a common language! I have heard of an AVO forever and always thought it was a brand name. I had to see DVM and AVO in the same sentence to realize that the item was a VOM! Live and learn. :doh:
Joe
Hi Joe,
Yes, the AVO which stands for "Amps, Volts, Ohms" became the brand name for the multimeter that for more than 60 years was the industry standard. The "Model 7" was aimed at the electrical market and the "Model 8" was aimed at the wireless/TV/electronics market. It's accurate 20K opv and mirrored scale set it apart from anything else.
There were variations of course, the AVO Minor, a pocket sized version, and the Model 8 with its seven or eight variants. All superb instruments, unfortunately no longer in production. In fact I don't think AVO as a company exist any more.
They don't as the company was bought up by Megger, which does still exist...
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Hi there, Baron,
Hi Pete,
You hang on to the AVO ! I have both AVO 7 and a pair of 8's. One over 40 years old. Digital meters are OK for some jobs, but there are many jobs where an analog meter can't be beaten.
:offtopic:
How do you cope with the 15 volt dry battery problem (for the high Ohms range)? Years ago, I saw a press review of a DC to DC converter that produced the 15 volts from the 1½ volt battery but it never seemed to catch on. Also, I never did work out how you switched it on.
Me neither :palm: I use a piece of thin plastic wrapped around ten AG10 cells clipped in place of the original battery. The only downside is the contact between the cells deteriorates with time and you have to take the pack apart and clean them. They seem to grow some kind of mold across the insulator as well.
By the way, my Senior Engineer mentor when I was a junior engineer used to emphasise that the Avo 8 is more sensitive than the Avo 7 (lower movement FSD) but the Avo 7 is more precise than the Avo 8 because the Avo 7 uses wirewound resistors while the Avo 8 uses carbon or metal film resistors!
The AVO 8 is 20K opv whilst the AVO 7 is 1K opv. As far as I am aware, bearing in mind circuit loading they are both the same.
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Thanks John,
I knew Megger was still around, but had no idea that they captured AVO.
Do they do the spares for them or is it just their own stuff ?
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Not that it's of any great significance but the B121 is not quite extinct ....
http://www.smallbattery.company.org.uk/sbc_a411.htm
Although the price would not appeal much ... :D
Dave
EDIT Whoops ... not in stock ... :scratch:
Could be a goner after all .... :zap:
Although there is a Varta 15v Battery and it looks like this is an adapter for same ???
http://uk.farnell.com/varta/v74px/battery-15v-10lf15-alkaline/dp/856174?ost=varta+15v
http://uk.farnell.com/avo-international/5210-064/adaptor-battery-avo-8/dp/4231454
So, looks like an easy job for that nice Mr Stevensons 3D printer ... :thumbup: