Silver Fox Class C

[Alan564017]

I have a Class C, came from across the pond DCC ready. Initially I fitted a bachmann 4 function chip (had one to spare) and it kangarooed around the track. So then I tried a bog standard hornby chip, it worked, it was fine at moderate and fast speeds but running it slowly was painful. It 'grinds' , its a horrible noise and the sensitivity at slow speeds is terrible compared to MM models. So I replaced that with a hornby sapphire chip, a little better but slow speeds are not great. Also the acceleration to poor, it takes a while to work its way up to a desired speed. Anybody got any ideas as to what CV settings are required to remedy both issues?

 

While im on a rant, it stalls over points and x crossings at slow speeds, I presume this is the insul frog-v-electro frog issue.

[Noel]

I have a Class C, came from across the pond DCC ready. Initially I fitted a bachmann 4 function chip (had one to spare) and it kangarooed around the track. So then I tried a bog standard hornby chip, it worked, it was fine at moderate and fast speeds but running it slowly was painful. It 'grinds' , its a horrible noise and the sensitivity at slow speeds is terrible compared to MM models. So I replaced that with a hornby sapphire chip, a little better but slow speeds are not great. Also the acceleration to poor, it takes a while to work its way up to a desired speed. Anybody got any ideas as to what CV settings are required to remedy both issues?

 

While im on a rant, it stalls over points and x crossings at slow speeds, I presume this is the insul frog-v-electro frog issue.

 

Models such as MM 141/181 run over our over Peco code 100 insul frog points very well at low speeds. There is the odd rare glitch, but most of the time the MMs crawl nicely over these insulated frogs. MMs are all wheel pickup on all bogies and are quite heavy so good contact with rails. I think the types of chassis most folks are using with SF A and C class are not all wheel pickup, hence the stalling over points at low speeds. Two remedies are to add more pickups (a time consuming job), or alternatively using a DCC decoder that supports external 'keep-alive' capacitors.

 

BTW, it is amazing sometimes how quickly loco wheels or track can get dirty, especially near the insulfrogs. The plastic frogs seems to attract dirt which attaches to wheels or rails near the frog. I've cleaned track work and sometimes its good for weeks, and sometimes I get unlucky and have to re-clean short sections only days after a decent clean.

 

In relation to slow acceleration, I had similar problems until I discovered CV3 and CV4 which control acceleration and deceleration (i.e. inertia), suggest setting both to 0 initially to see how loco runs and then incrementally increase their values until you achieve suitable inertia for that motor and gear box combination. This is relatively new to me but being an IT bod, I've had my head in manuals and been experimenting with DCC for the past three months and it is still a learning curve.

 

The grinding noise you experienced could be due to BEMF settings unsuited to the motor in your chassis. CV8=8 decoder reset will put all the settings in your decoder back in a factory default state including the loco address back to 3, but you can then experiment with the CVs for BEMF on your particular decoder (e.g. on or off or change the levels).

 

BTW, its a pain cleaning wheels on DCC locos as I have to temporally switch DC/Analog mode on the decoder, before putting the loco upside-down in a cradle using the electrified peco cleaning probes (i.e. connected to DC source).

 

I'm sure other more experienced on here who have SF can recommend decoders and settings that have worked for them.

Edited December 1, 2014 by Noel
Lexdisia

[Alan564017]

Models such as MM 141/181 run over our over Peco code 100 insul frog points very well at low speeds. There is the odd rare glitch, but most of the time the MMs crawl nicely over these insulated frogs. MMs are all wheel pickup on all bogies and are quite heavy so good contact with rails. I think the types of chassis most folks are using with SF A and C class are not all wheel pickup, hence the stalling over points at low speeds. Two remedies are to add more pickups (a time consuming job), or alternatively using a DCC decoder that supports external 'keep-alive' capacitors.

 

BTW, it is amazing sometimes how quickly loco wheels or track can get dirty, especially near the insulfrogs. The plastic frogs seems to attract dirt which attaches to wheels or rails near the frog. I've cleaned track work and sometimes its good for weeks, and sometimes I get unlucky and have to re-clean short sections only days after a decent clean.

 

In relation to slow acceleration, I had similar problems until I discovered CV3 and CV4 which control acceleration and deceleration (i.e. inertia), suggest setting both to 0 initially to see how loco runs and then incrementally increase their values until you achieve suitable inertia for that motor and gear box combination. This is relatively new to me but being an IT bod, I've had my head in manuals and been experimenting with DCC for the past three months and it is still a learning curve.

 

The grinding noise you experienced could be due to BEMF settings unsuited to the motor in your chassis. CV8=8 decoder reset will put all the settings in your decoder back in a factory default state including the loco address back to 3, but you can then experiment with the CVs for BEMF on your particular decoder (e.g. on or off or change the levels).

 

BTW, its a pain cleaning wheels on DCC locos as I have to temporally switch DC/Analog mode on the decoder, before putting the loco upside-down in a cradle using the electrified peco cleaning probes (i.e. connected to DC source).

 

I'm sure other more experienced on here who have SF can recommend decoders and settings that have worked for them.

 

Cheers Noel, the MM models are no problem over points and you touched on the issue of the SF not being all wheel pick up (not a job I will tackle) which causes the stall. I'll mess around with the CV'S, do you know which CV deals with BEMF?

[aclass007]

While there may be some DDC related issues that you can address, I think the basic problem here is the motor used in the Silver Fox locos. Basically, a simple pancake motor from Hornby or Lima, and as mentioned, pickup isn't on all wheels.

[Alan564017]

While there may be some DDC related issues that you can address, I think the basic problem here is the motor used in the Silver Fox locos. Basically, a simple pancake motor from Hornby or Lima, and as mentioned, pickup isn't on all wheels.

 

007, agreed, its a simple motor, the info that comes in the box (VERY limited) says its from a hornby class 58 chassis. Its the 'grinding' that bothers me, compared to MM's its very annoying. With that said, I have other hornby models (deltic and pullman) and at low speeds they do the same thing although not as bad.

[Noel]

007, agreed, its a simple motor, the info that comes in the box (VERY limited) says its from a hornby class 58 chassis. Its the 'grinding' that bothers me, compared to MM's its very annoying. With that said, I have other hornby models (deltic and pullman) and at low speeds they do the same thing although not as bad.

 

Hi Alan. I haven't had time to find out what CVs control BEMF on that hornby decoder, by some folks on here should know. Just to let you know, a few times when experimenting with decoder settings on MM 141 and 181s I also got that noisy grinding when I screwed up the BEMF settings, so I suspect this can be cured. Some decoders also have a nudge/pulse system which can upset older motors, but this can be disabled. When I first converted some of my old non-DCC ready steam locos to DCC a few months ago, I had similar problems, but got around them by experimenting with different motor CVs.

[irishthump]

The BEMF adjustments are limited on the Sapphire, but CV 150 has 2 settings to suit different motor types. CV 150 can be set to either 0 or 1 and if I remember correctly a value of 1 is for older motors. Might be worth a try....

 

But you have to bear in mind that this motor will never run as well as the MM locos. MM's are equipped with a good quality can motor and flywheels which improve slow running considerably, you will probably get the 58 motor running smoothly but it's slowest (reliable) speed will be higher than an MM. I would concentrate on getting the loco to run steadily at speed step 1.

[Alan564017]

thanks irish, i'll give that a try. I understand that it will never perform as well as an MM but then again what can!!

[Blaine]

Surprised our resident expert has not suggested swopping in a MM 141 chassis....almost a direct fit....

[Noel]

007, agreed, its a simple motor, the info that comes in the box (VERY limited) says its from a hornby class 58 chassis. Its the 'grinding' that bothers me, compared to MM's its very annoying. With that said, I have other hornby models (deltic and pullman) and at low speeds they do the same thing although not as bad.

 

Update. The SF A class we got came on a Hornby class 55 chassis. The model came with a basic Hornby decoder and it had a 'grinding' noise at low speed. I have just replaced the Hornby decoder with a Lenz standard 8 pin decoder and the 'grinding' noise is gone. Loco runs quieter and smoother at low speed and at least CV2,3,4,5,6 now all work. The Lenz decoder cost €12 despite RRP of 17.

 

I've decided to standardise on Lenz for non sound decoders and Zimo for GM sound decoders (141/181, 071).