Polar 55EM No Display etc

We have had a number of intermittent faults with our guillotine over the last few years, but now the display has stopped working.

On occasions in the past the display might go off, but switching the machine off and back on often 'cured' the problem.

Also a few months ago the machine would move very slowly when operated. That seemed to put it's self right, but then when we set the size to cut, the machine would operate, but would stop just less than the size typed in. Sometimes typing in the size again put this right, but usually we have adjusted the size manually.

The current situation is that there is nothing displayed at all, apart from the decimal point and a zero. All we can do is move the backgauge using the forward and back buttons on the display board. (Fast forward and back doesn't work) We are having to manually measure the backgauge possition.

Any help would be appreciated. Our operating manual is an old photo copy, so if anyone could let us have a pdf version of this or of a manual, that would be great.

Sorry for the epistle!

 

Hi!

Usually the CP55 board behind the keyboard is broken. And this board is not cheap. I think even after 30 (!) years there are spare parts available. But check the price first.
The only alternative I can think off is the power supply for this board. The board CP55 is supplied with 9V d.c. at the plug X550 Pin 4 (to pin 1 which is 0 V). The board itself is changing this power supply to 5 V d. c. If I remember correct there are two measurement points on the board. The tolerance for this voltage is 5.08 to 5.12 V d. c. I think there is a potentiometer (R5) for the adjustment as well. If the voltage is to low you have the same problems.

Good luck

Coloured paper

 

Hi Coloured Paper.
Thank you for your very quick response.
I will ask a friend of mine to checkout the board for me, as I'm not very good at electronics. My background is in mechanics.

 

Hi Coloured Paper.

I'm still waiting on my friend to check out the items you suggested. However, I've found out something more about the problem.

When the problem with the display occurred, and I could no-longer set the cut sizes, I was using the forward and back buttons and on occasions they didn't work either.

What I realised today is that after I switch the guillotine on at the main switch, if I then push the back button there is a click from something on the right-hand side of the machine (E55 switch board?) and nothing moves. If I then press the red button on the main display (There is a loud click from the rear of the machine), followed by the "C" button, the forward and back buttons will operate again.

Could this also be a symptom of the CP55 board fault?

Thank you for your help.

 

Hi!

I think the noises are the relays to activate the backgauge motor and the backgauge motor brake. This would be normal.

Take your time
Coloured paper

 

With age, this board is prone to Instability ( 5v supply becomes unstable) - high frequency oscillation.
This is due to degradation of it's electrolytic capacitors.

These are not difficult to replace -- make sure you install them the correct way around -- (ie correct polarity).

Replace with at least the same Voltage devices (Higher voltage Caps are acceptable)
Replace with at least same Capacity, Up to x2 the original capacity is acceptable.

Adjust voltage on Test points to 5.10 ( NOT 5.00).
If Voltage is still unstable, over time, then the actual Regulator IC may need to be also changes.

Unless this power supply is putting out a stable, consistent 5.10 v DC, over time, you will continue to have all sorts of intermittent, varying issues.

Geoff

 

Hi Geoff and Coloured Paper

Thank you for your help.
We checked the voltage, which seemed to be ok. I'll suggest to my friend that we replace the capacitors etc. They must be cheaper and easier than trying to locate a new board.

 

YES There is no such thing as a "new" board for this machine, and any old/repaired/exchange boards will probably also be suffering from aging Caps, to some extent.

New Caps is an easy/cheap solution .. and should cure any Regulator oscillation/instability.

 

Hi Geoff and Coloured Paper.
We've replaced all of the capacitors on both the CP and BT boards, as well as the Regulator IC.
However its still the same. The Caps and Regulator we about 30 years old, so it was worth replacing them anyway and they cost only coppers.
I don't know if this helps but when I first switch the machine on, (before I try the forward and back buttons on the BT board) if I double press the Red button all of the display lights up with the number 8 as well as the symbol keys at the right-hand side lighting up. After holding the Red button for a couple of seconds there is a click from one of the "monitoring relay's" k21c /d/e/f/ and the display goes off.
I can continue doing this, until I press the cancel button to allow the forward and backward buttons to work.
Regards
Bill

 

The double klick is starting a test sequence. This is called "lamp test". This is correct.
If you did not perform the complete reference run you may change by using the "C" button to the auxiliary function. This is a test mode to check the backgauge drive without measurement. To go back to normal operation, you do a reference run.
Coloured paper

 

Hi, Coloured paper, send your email to contact.

Greetings.

 

Bill, if you don't carry out a reference Run then there will be no numbers on the display.

Unfortunately I'm finding more older machines that either the cable to the linear Scale fails or the reader head has a fault, in your case could be an missing z pluse.

Which I've had on one 55em the A and B worked but it still never worked because the Z set pluse had failed in the head.

The other day I worked on a 76 that had a massive multiple z pulse after a clean and oil it was fine.

We have a new replacement option if it is needed as we can supply a new linear encoder at a fraction of the cost of polar.

But it might be needing a clean.

Regards rob

 

Hi rspblake!

Regarding safety
Health and Safety in the UK used all there power to get EN1010 going and now you will say there is nothing????

Technicalwise.
If you have the lead screw (241507) for the backgauge in a 55 machine which has a tolerance of 2 mm per meter length and you pickup the position with an encoder you are per meter 2 mm out of measurement. Do you tell your customers about the risk of a wrong measurement. Perfect!

Coloured paper