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New Product Announcements / BR mark 1Ventilators
« Last Post by Gavin_B on Yesterday at 02:09:54 PM »
New products from Marston Models.

3d printed ventilators for BR mark 1 coaches.  Three types, Ridge, Dome and shell.

£4 for 10.



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Hello All

For what it's worth Hornby Doublo make 1000's of them in the 50's & 60's . Pic's available on request . Very nice they are too .
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Other Topics / Re: Greedy Motors + "Picky" ESC = Big Headache!
« Last Post by John Candy on October 13, 2018, 07:10:19 PM »
Ralph,

I haven't replaced the faulty cells, since I don't require the additional voltage..... the 18 cell pack was charging to 24.85V ...... that one "fried" the 24V-rated Viper 10 HV ESC ...... and now charges to 23.5V with 17 cells, while the pack which was formerly 16 cells but is now just 15 is charging to 21.04V. These two are higher voltages than fitted in my other locos..
I don't have any shrink wrap large enough to encapsulate the packs but all exposed connections and bare metal surfaces have been given three coats of "Reformix Liquid Tape" (a paint-on rubber insulation sold for automotive use).

Regards,
John.
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Other Topics / Re: Greedy Motors + "Picky" ESC = Big Headache!
« Last Post by cabbage on October 13, 2018, 05:46:55 PM »
John,
Hopefully you replaced the ruined cells with tagged cells of  same capacity!

Regards

Ralph
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Other Topics / Re: Greedy Motors + "Picky" ESC = Big Headache!
« Last Post by John Candy on October 13, 2018, 08:13:31 AM »
In the course of sorting out the railcar motor bogie issues, I have learnt a bit about detecting and isolating  faulty cells within a battery pack.

I use the Axtronics Smart Chargers (as supplied by Strikalite) in conjunction with the same suppliers NiMH cell packs.

I have deduced that when you plug into the charger a "good" cell pack, the RED charge light illuminates immediately and stays on until the pack is fully charged, whereupon the GREEN light comes on. If the RED light comes on and goes out after a couple of seconds, then the GREEN light comes on and goes out after a couple of seconds, followed by the RED coming on and staying on, then you have a "problem" cell pack.
The light will eventually go GREEN (indicating a full charge) BUT, although the voltage will indicate a "full charge", you may find that the pack is NOT charged to capacity in terms of mAh and will run down very quickly. Another indication is when the voltage "decays" very quickly under load. The pack may indicate 20V when unconnected but attach a motor and (monitoring the voltage with the motor running) the voltage will quickly reduce to only a few volts ( a "good" pack will maintain a steady voltage under load). When the load is removed, the voltage will spring back to the 20V (or whatever the nominal voltage of the pack) so checking voltage of a disconnected pack will not give a reliable diagnosis of battery health.

I had two packs which gave a "dodgy" signal with the Axtronics charger, so I stripped away the shrink wrap and tested the individual cells. In one pack (which had the older style green/opaque shrink wrap) I found a single cell which had leaked and corroded and was giving a reading of only 1.06V, whereas all the other cells in the pack were reading 1.38V. I removed the "dud" cell and reconnected the remaining cells and the pack is now charging as it should to the rated capacity of 2100mAh. The second pack had the more recent transparent shrink wrap and there was no sign of leakage or corrosion but one cell was reading just 860mV, whereas all the others were reading 1.4V. As with the first pack, I removed the "dud" and the pack is restored to normal health.

So, before you throw away a seemingly dud pack, it is worth checking the voltage of the individual cells and removing/replacing any which are more than 150mV below the remainder. 
Photo shows the leaking/corroded cell.

John




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Help Required / Re: Dummy Rivets.
« Last Post by 492 on October 12, 2018, 12:53:36 PM »
The ball bearings came from this site on ebay. iI you need 64th size imperial, we suggest that you try American suppliers on Ebay.

https://www.ebay.co.uk/itm/1mm-G16-Grade-Hardened-Carbon-Steel-Loose-Bearing-Balls-Choose-Order-Qty/281673249069?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Hope this is helpful.
Robert. 492.
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Carriages & NPCS / Re: GRS B set coach mod & Cliff Barker CCT kit
« Last Post by hornbeam on October 12, 2018, 09:40:16 AM »
Must confess one end of the body casting was damaged on mine and I’m sure your aware John the ends are very thin. Only mod I did to mine was to add an internal partition to strengthen it up a bit.
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Carriages & NPCS / Re: GRS B set coach mod & Cliff Barker CCT kit
« Last Post by John Candy on October 12, 2018, 08:41:40 AM »
I agree with comments on the GRS kit.
It is very many years since I built my example but, from memory, the only major alteration I made was to the castings for the end vent hoods....they extended too far down as supplied.
There was a small chunk missing from one of the vertical side angle irons (must have been broken off when casting was removed from mould) which I patched with thin plastic card.
Only real "grouse" is with the transfers..... the typeface/font of the numbers isn't correct....in particular the figure "2" but can live with that!
One of the best of the GRS rolling stock kits.
John.
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Help Required / Re: C37 Details or even Drawings
« Last Post by cabbage on October 12, 2018, 08:36:26 AM »
Tim,
Yes I have! Plus a bag of Goji Berries...

Regards
Ralph
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Carriages & NPCS / Re: GRS B set coach mod & Cliff Barker CCT kit
« Last Post by hornbeam on October 12, 2018, 08:29:39 AM »
I have built the GRS version and it’s not a bad kit to make, nice crisp resin castings for the sides and ends.
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