ECM Compspeed circuit

[robertc]

Hi Clive, probably as Cliff has stated. 

As for the unnamed poster, the current handling  limitation remains in the reversing switch which is nothing more than some sliders on pc board tracks. Adding an external reversing switch does not solve that issue.

cheers

Bob Comerford

[kevinlms]

12 hours ago, Clive Davies said:

Another Compspeed matter you might be able to help with, as a result of lying on the floor looking up at the underside of the layout and being bemused by the pile of spaghetti there, too many wires the same colour etc: done over many years with bits added on here and there, I decided to rationalize the wiring and have some sort of diagram so I new what was what. Discovered I probably wired the controllers up incorrectly. Compspeed instructions state (the input voltage must not exceed 14-18volts AC and each unit must be wired to it's own isolated winding, ie: one pair of orange wires per winding.

DO NOT CONNECT MORE THAN ONE UNIT TO ONE WINDING.)

I have to say that's exactly what I didn't do,  both wired to one transformer, it's fairly meaty at 5 amps and a single 16 volts AC output.  DC rectification is done within the controllers of course.

They have been wired this way for years  and nothing seems to have suffered any detrimental effects. I have no memory as to why I ignored their instruction or perhaps I didn't read them properly. Have I got away with it because I don't have it on for long periods, and if it was on for long periods would the transformer get very hot  despite having more than adequate power ? Two separate transformers or a single new trans with two 16v windings ? Very interested to hear what people think.

An issue with a large power supply like that is, in the event of a short circuit, that power supply is going to keep pumping out power for ever. Unless you include some other sort of protection to the controllers. 

[Junctionmad]

Quote

 think that was me. I do have some hand drawn sketches of the circuits for a standard Mk I, a centre off version and the Rambler Minor. I'll try and scan the drawings later today, not sure how well they will come out. Also not sure if I would be breaking any copyright if I put them on here, but I can always email them.

 

If there were drawn up by you based on reverse engineering the circuit there is no copy right issue , as you cant copyright a design or an idea, merely a written description of it 

[Junctionmad]

Quote

Another Compspeed matter you might be able to help with, as a result of lying on the floor looking up at the underside of the layout and being bemused by the pile of spaghetti there, too many wires the same colour etc: done over many years with bits added on here and there, I decided to rationalize the wiring and have some sort of diagram so I new what was what. Discovered I probably wired the controllers up incorrectly. Compspeed instructions state (the input voltage must not exceed 14-18volts AC and each unit must be wired to it's own isolated winding, ie: one pair of orange wires per winding.

DO NOT CONNECT MORE THAN ONE UNIT TO ONE WINDING.)

I have to say that's exactly what I didn't do,  both wired to one transformer, it's fairly meaty at 5 amps and a single 16 volts AC output.  DC rectification is done within the controllers of course.

They have been wired this way for years  and nothing seems to have suffered any detrimental effects. I have no memory as to why I ignored their instruction or perhaps I didn't read them properly. Have I got away with it because I don't have it on for long periods, and if it was on for long periods would the transformer get very hot  despite having more than adequate power ? Two separate transformers or a single new trans with two 16v windings ? Very interested to hear what people think.

The only issue with this is where the two controllers meet via a connected track and one controller is in " reverse " , at that point you will create a short , but the comspeed ( from memory ) has short circuit protection .  The proviso in  red you mention is largely if the layout is wired as Common Return . 

 

Where you connect multiple AC devices , ie each controller has a bridge rectifier , there can exist an imbalance in the ground return circuit where potentially current from one controller can return via the ground of another , often exceeding the specifications of the bridge rectifier.  The common solution is a very small value resistor in the DC ground line . However in many cases the issue simply never materialises  ( to the extent that it causes issues ). MERG  AC powered  kits often added this resistor as they were driven off a common AC bus 

 

 

 

Edited May 11, 2019 by Junctionmad

[Clive Davies]

Thanks all, some good advice. The two rail circuits (inner and outer) are not connected in any way,

so probably not a problem then, but I do have another transformer under the board which operates a lighting circuit (some LED and some grain of wheat)  It handles 2 amps so I'm tempted to use this to power one of the controllers anyway.  ECM instructions state that the transformer should be able to handle 1.5 amps  so 2 amps is more than enough and it can operate the GOW

bulbs as it has 17/15 /12/10 volt outputs and I prefer to run them at 10v which makes them a bit dimmer and more realistic.  they don't care if the voltage is AC or DC. The LEDs  can then go from the bigger transformer with rectifiers at appropriate points. .  Both controllers outputs go via 1 amp circuit breakers and there are ammeters and voltmeters on both circuits letting me know how well the loco is running.   Thanks again for the reply's.

 

[57xx]

 

On 05/05/2019 at 12:57, dhjgreen said:

RE identifies it as an RCA part

 

It's BE. The B means is a 4000 Series B chip and it's got buffered outputs to the gates (as opposed to a CD4001UB which would be unbuffered). I think the E denotes the package type, in this case 14 pin DIL. The "CD" prefix historically denotes it's an RCA part, although other manufacturers (e.g. TI) also use this prefix.

[5050]

I have a couple of Ramblers which I think is a brilliant controller - when it works!  Mine have stopped working and nobody is prepared/able/willing to repair them.  A Rambler would be ideal for my latest small shunting plank.  The reversing relay seems to work (a slight 'click' when the direction is changed?) but control is non-existant.  Len Rich did repair one for me once but sadly, as someone has already said, he didn't leave any details for us to work from.

 

Is there any hope of reviving them?  I've no aptitude with electronics and my knowledge of electrics is that current flows from negative to postive (or is it the other way round!?) and that high currents can kill you if you're not careful!

 

BTW, one of the Ramblers is a 'new in box' unused one that I bought 'pre-owned' at an exhibition a couple of years ago - but it doesn't work either.

[RobjUK]

22 hours ago, 5050 said:

Is there any hope of reviving them?  I've no aptitude with electronics and my knowledge of electrics is that current flows from negative to postive (or is it the other way round!?) and that high currents can kill you if you're not careful!

 

I'd have a look if you want to send one to me, just for the cost of postage back if that is significant.

 

I have been repairing electronics as a profession for around 40 years..

 

PM me if of interest.

RJ.

[5050]

On 20/06/2019 at 21:27, RobjUK said:

 

I'd have a look if you want to send one to me, just for the cost of postage back if that is significant.

 

I have been repairing electronics as a profession for around 40 years..

 

PM me if of interest.

RJ.

Many thanks to Rob as this has now been done and it seems to work well.  I wonder what the reaction will be at exhibitions when people see it in use.  Will some think it's the latest gismo (those under 30 years of age probably) or will they look on in amazement (those over 30) that such a piece of ancient (!) electrical history is still in use?

[RobjUK]

Hi,

you are most welcome.

 

They are an interesting little controller and amazingly good!

 

RJ.

 

[Junctionmad]

Does  someone now have a full schematic ? 

 

Dave 

[sharris]

5 hours ago, 5050 said:

Will some think it's the latest gismo (those under 30 years of age probably) or will they look on in amazement (those over 30) that such a piece of ancient (!) electrical history is still in use?

Looking at my hifi rack, I see that my CD player is about 32 years old, and my turntable and speakers a few years older and still sounding good. Will those under 30 be asking 'what's a CD?' (let alone a record!)

[RobjUK]

4 hours ago, Junctionmad said:

Does  someone now have a full schematic ? 

Unfortunately, no..

The type of fault did not mean I had to fully disassemble the controller and get to the inner circuit board.

 

I was rather curious how the up/down button system worked, but I was not prepared to desolder things unnecessarily just to satisfy my curiosity.

 

1 hour ago, sharris said:

Looking at my hifi rack, I see that my CD player is about 32 years old, and my turntable and speakers a few years older and still sounding good. Will those under 30 be asking 'what's a CD?' (let alone a record!)

 

Mine varies between something like probably 40-50 for the main speakers (Goodmans Achromats) and JVC linear tracking record deck to current for the rear / surround speakers and active sub (B&K) and a Sony surround amp. 

"If it ain't broke, don't fix it!"

 

Under 30s or teenagers may be confused by Record or LP, in the current fad they are called Vinyl - and typically played on unbelievably bad turntables / record decks with MP3 or bluetooth output - they just do not see the laughable side of that, the supposed and mostly fictional "quality" of LPs fed through lossy digital compression systems....

 

[57xx]

On 19/07/2019 at 14:51, 5050 said:

I wonder what the reaction will be at exhibitions when people see it in use.  Will some think it's the latest gismo (those under 30 years of age probably) or will they look on in amazement (those over 30) that such a piece of ancient (!) electrical history is still in use?

 

You would get a big thumbs up from me, I have a Rambler Minor upstairs. I haven't actually wired it up to test out if it still works though. After reading this, I'm thinking I need to do so.