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As I now have a quantity of very cheap MRC AD322 decoders I am experimenting with various locomotives to put them into.

http://www.modelrec.com/search/product-view.asp?ID=1271

My newest "victims" will be some of my older Aristo-Craft FA-1's and FB-1's.

While the locos are a few years old they have extremely little running time so part of my objective is to give them more use by turning them into multi-user locomotives by enabling easier operations for visitors who will be running them under LGB's MTS.

There are a couple of things I should mention:

1. I am not doing full decoder installations. Since I still run primarily analog track power I will continue to handle the train operations with traditional track power operations (electrically blocking sidings, track magnets for sound activation etc.). As a result my primary purpose of installing the decoders is to enable selective locomotive operation by different individuals.

2. My primary objective is to achieve MTS/DCC operations at the lowest possible cost. My choice of the MRC decoders is based strictly on their very low cost. I do not suggest that they are in any way the best choice - just the cheapest I have found that seem able to do the job.

3. The diesel sound from the MRC decoders is not impressive but I could live with it. I have a quantity of LGB 4235s (analog powered) sound units from LGB sound cars and since I already have them I will be installing them instead of using the sound system of the decoders. Others might want to use the MRC sound if they do not have or want to buy sound systems.

4. The MRC decoders are discontinued older models and are somewhat temperamental when switching between MTS/DCC and analog track power. Sometimes they try to go forward when they should reverse and sometimes when switching from analog to MTS they will take off at high speed (I'm still figuring this out).

5. I am not making any recommendations or suggestions that anyone should do anything. I'm just showing what I am doing in case it may be of interest or assistance to anyone. If nothing else the circuit diagrams might be helpful.

6. This is a work-in-progress. It is accurate and up to date as far as I know. On the other hand there could be errors that I have not yet discovered.

This is the wiring diagram I have developed so far:



Jerry
 

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Discussion Starter #2
It has occurred to me that some of the "temperamental" actions of the AD322 decoders might well be the result of its having a mechanical relay.

Perhaps the slight delay in the relay changing positions might be causing the directional control issue with analog power and the directional surge under MTS.

It may be that this decoder when used with the FA-1's and FB-1's (as I found with Lionel 0-4-0's) might work best with a physical switch to operate on analog power without going through the decoder and then switch the loco input from direct track contact to decoder output.

Eventually I may try that and see how it works out.

Jerry
 

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Jerry-


Perhaps the slight delay in the relay changing positions might be causing the directional control issue with analog power and the directional surge under MTS.
It may be that this decoder when used with the FA-1's and FB-1's (as I found with Lionel 0-4-0's) might work best with a physical switch to operate on analog power without going through the decoder and then switch the loco input from direct track contact to decoder output.



To paraphrase, the decoder might work better in analog if it is not used.

This is certainly an option. In analog, the loco would be driven straight from the original electronics. Of course, since you are dealing with old versions of the Aristo FA-1/FB-1, the motorblocks aren't isolated, i.e., Aristo did not provide four electrically isolated pins for left motor, right motor, left rail, right rail. This makes matters a bit more complicated, but not impossible.

Best regards,
Bob
 

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Discussion Starter #4
I believe the Aristo-Craft motor blocks ARE isolated and as a result, putting a MTS/Analog switch into the circuit should be quite simple.



My original challenge in fitting the decoders to the FA-1/FB-1 was not the motors - it was the frame circuit board because it was the circuit board (not the motors) that connected one leg of the motor to one side of the tracks.



Of course Aristo-Craft made various versions of motors/drive units and circuit boards and my concern is for the version I have. I believe all of my FA-1's and FB-1's have exactly the same circuit boards and motors. When I bought them I bought a surplus to enable me to upgrade all the ones I kept to the then latest models.

Jerry
 

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Jerry-

You wrote:

I believe the Aristo-Craft motor blocks ARE isolated and as a result, putting a MTS/Analog switch into the circuit should be quite simple.

My original challenge in fitting the decoders to the FA-1/FB-1 was not the motors - it was the frame circuit board because it was the circuit board (not the motors) that connected one leg of the motor to one side of the tracks.



The motorblocks are only isolated after you modify the locomotive circuit board. (That was my original point.) Newer Aristocraft locos are DCC-ready, i.e., there are four isolated connections for the left rail, right rail, left motor, and right motor.

Best regards,
Bob
 

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Discussion Starter #6
Actually Aristo DID provide four separate pins for left motor, right motor, left rail, right rail for each of the motors:



By connecting the four wires from each of the motors to the circuit board with removable jacks Aristo-Craft made splicing into the readily accessible wires much easier and safer than having to solder to pins on a motor. The motors/drive units never had to be removed from the frame.

I never modified the circuit board. I simply spliced into the two track wires between each of the motors and the circuit board.



The color coding I showed of the bottom of the circuit board earlier was so signify the color coding of the wires on top and how the circuit fed them to the motors.

Jerry


Posted By rwbrashear on 09/02/2008 3:14 PM
Aristo did not provide four separate pins for left motor, right motor, left rail, right rail. This makes matters a bit more complicated, but not impossible.
Best regards,
Bob
 

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Jerry-


Actually Aristo DID provide four separate pins for left motor, right motor, left rail, right rail for each of the motors:



There are separate physical pins, but if they are electrically connected, the motorblocks aren't isolated. I am not sure why you are choosing to argue about this fact. HO scale locos often have isolation issues caused by shorting wires to the frame/chassis. Electrically, it's all the same, just location of the short between the motor and track leads changes. To install a decoder, there needs to be four isolated leads.

Best regards,
Bob
 

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Discussion Starter #8
My point is simple.

The motors ARE isolated and if my circuits are followed they remain isolated.

The circuit board is not part of any motor and it can be quickly and easily unplugged from the motors.

Your statement was incorrect (misleading if you prefer) in that you incorrectly implied that Aristo did not isolate their motor leads from their track leads.

You suggested Aristo complicated decoder installation when in effect they made decoder installation much easier.

I don't know (once again) why we are having a discussion in the first place. I think my diagrams and explanations are pretty easy for anyone to follow.

Jerry
 

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Jerry-

You suggested Aristo complicated decoder installation when in effect they made decoder installation much easier.



This is an odd statement, especially following your comments on other forums. If I remember correctly, you reported trouble with the first FA-1 DCC installation because you did not recognize the fact that the motor/rail leads were shorted on the circuit board. Connecting a DCC decoder to a non-isolated locomotive is an excellent method of destroying a decoder. If your decoder didn't fry, well, you were lucky. For someone following this thread, the non-isolation condition is fairly important information.

Aristo has fixed this issue with later version locos which include the DCC interface. The interface provides easy connection of DCC decoders, without surprises.

Best regards,
Bob
 

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Discussion Starter #10
My previous comments on the other forum as well as my current comments on this forum were/are related to the same Aristo FB-1. I just now finished with my modifications to it.

As I pointed out in the other forum it was the circuit board that shorted out the motor to the track leads. I pointed out the same thing in this forum. The circuit board is not even needed with this or the other decoders. I just chose to leave it in and make my decoder installation to include the circuit board.

My diagrams clearly pointed out that the decoder was being connected to the motor BEFORE the motor was connected to the circuit board. The diagrams also clearly show that the circuit board places a direct short across the motor/track leads.

Certainly a new Aristo loco with a DCC interface would be a much more logical and easy loco to convert to DCC.

As I stated, this topic is about:

"My primary objective is to achieve MTS/DCC operations at the lowest possible cost. My choice of the MRC decoders is based strictly on their very low cost. I do not suggest that they are in any way the best choice - just the cheapest I have found that seem able to do the job."


It is about the ability to convert a older model Aristo-Craft locos to DCC (including diesel sounds) for only $10.99.

The MRC AD322 Diesel Sound decoder is what makes it possible to make such a cheap conversion for older Aristo FA-1 or FB-1 locos. The topic is involves controlling nothing more than the motor output of the decoder (unless someone wished to use the diesel sounds through the functions on the decoder.

I also said:

"5. I am not making any recommendations or suggestions that anyone should do anything. I'm just showing what I am doing in case it may be of interest or assistance to anyone. If nothing else the circuit diagrams might be helpful.

6. This is a work-in-progress. It is accurate and up to date as far as I know. On the other hand there could be errors that I have not yet discovered."

Jerry
 

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Discussion Starter #11
I might add that if anyone is considering making a conventional decoder installation into these older Aristo FA-1's and FB-1's that they should keep in mind that the short from motor lead to track lead (blue wires) is probably not just confined to the frame circuit board.



Since the circuit uses the blue wire from the frame to the body for both one side of the motor leads and one side of the track leads it is quite possible that the other circuit(s) in the body of the loco may also have similar combined motor/track wiring.

I have never attempted (or plan to attempt) a conventional decoder installation into an Aristo FA-1 or FB-1. Such an installation would (I would guess) involve wiring everything direct to the decoder rather than to use the existing circuit boards.

This topic is not intended to be a guide to conventional decoder installations. It is just a single purpose installation that does nothing more than to trick the loco into running under MTS/DCC as if it was still being powered by analog track power.

I am not a MTS/DCC expert. I am just figuring out how to add very limited MTS/DCC capability to my analog track powered layout at the lowest cost.

Jerry
 

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I have now completed the installation of the MRC AD322 decoder and LGB 4267s (analog) sound unit into an Aristo-Craft FA-1. That now gives me a AB set with the same configuration to check out double heading.

The FA-1 installation went ahead very smoothly since it was wired exactly the same as the FB-1 I had done first.

The only problem was that I had to relocate the LGB sound board because the cab of the FA-1 did not allow enough space for the sound board under it.

Once I connected the FA-1 and FB-1 my suspicions were confirmed in that the switching between analog track power and MTS/DCC resulted in unacceptable pushing and pulling as the decoders switched from track power to DCC.

I will next reprogram the decoders to DCC operations only and put a DPDT switch in the locos to manually switch to track power independent of the decoders.

It is a challenge but if I can end up with a F-1 ABBA set running on analog track power AND on MTS/DCC for a total of less than $50 it will have been a successful venture for me.

Jerry
 

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The first installation (FB-1) took me quite a long time as I had to figure out how to do everything.

Now that I have made wiring diagrams the 2nd loco (FA-1) went MUCH faster.



The third loco (another FB-1) went amazingly fast.



I thought I had run into a significant problem but it turned out that I had apparently damaged the first FB-1's decoder (not at all surprising since I had caused at least 3 major shorts of it as I played with it and installed it. What was surprising was that it survived the first shorts with no apparent damage. The good news is that I only ruined a $10.99 decoder. Even with the burned out decoder I am left with spare wiring harnesses and a spare speaker. Most places would have charged $10 just for the wiring harness.

Now that I know what I am doing and I am being more careful (watching for the carpet with a bit of melted solder on it - and watching for bits of cut off wire strands - and insulating dangling unused wires from the decoder) the installations are proceeding fast and trouble free.

The last FA-1 will be a bit slower because I have to first take a LGB 4267s sound card out of a USA GP-9 and install a Sierra sound system in it so I can put then put the 4267s sound card into the final FA-1.

I'm removing Aristo-Craft digital sound systems from the PRR FA-1's so that the PRR ABBA set will all have LGB 4267s sound systems and the Aristo sound units will go into another ABBA sets "B" units so that the other F1-ABBA set will have Aristo digital sound systems in all the ABBA units.

The LGB F7's impressed me with how much more I liked having sound from all four ABBA diesel locos.

Jerry

Jerry
 

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I should add that by disabling the analog track power on the decoders that the problem with short bursts of speed when switching MTS on has gone away.

First I ran the FA-1 under MTS. Then I ran a AB set and finally I ran the ABB set and everything worked very well.

I even programmed the 2nd FB-1 to run in reverse (as I will also program the 2nd FA-1). This way I will be able to run them as an ABBA set under MTS all with the same Loco ID #.

I was concerned that the 2nd FB-1 (running in reverse) might not match the speeds of the FA-1 and FB-1 (running forward) but the three locos run together without any apparent problems.

Since everything in the locos runs off the motor output of the decoder a nice benefit is that I don't have to worry about excessive voltage going to the lights etc. since the brightness is controlled by the throttle (just as with analog track power).

An unforeseen benefit is that if the decoder does not read serial commands it will not matter because when running under analog or when running under MTS under either serial or parallel mode, when I stop the loco everything shuts down. No lights, no motor - nothing runs. This should minimize volt/amp drain by locos sitting on the main line that are not running.

For the price of these decoders I might even be tempted to put decoders into the passenger cars so that I can remotely dim or turn off the lights on inactive cars so they do not push me to the MTS 5 amp limit too soon.

Jerry
 
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