C8217 Powerbase trouble shooting

[Scott1707822906]

I'm trying to get a 22-year-old "Le Mans Sports Cars" T2 set running. The set has a C8217 powerbase. When I operate the trigger, the cars sort of hum and vibrate but do not move. The cars run fine on my other (different brand) track.

Voltage at the power transformer barrel connector is about 19 volts AC.

Voltage at the tabs under the track (where the leads from the powerbase connect to the rails) is under 1 volt.

Do these powerbases fail?

Is there someplace on the printed circuit board where I should test?

Stumped in WA,

--scott

[Andy P.]

Hi Scott,

First of all I want to thank you for probably one of the best "troubleshooting" posts I have seen in a long time!

Most of the posts are "car no go" or "smoke go out" and I have to start a conversation asking and hoping for an answer (which often never comes).

Your pictures are also top notch in that they are clear and easy to read.

The C8217 was the main power base for analog sets for over a decade. It is also considered by many as the "best" because it allows braking and you can plug in two powerbases to help ensure power flow all around the track.

They are usually really robust so one going bad is very rare.

Couple of questions:

1. You say "another brand": Are the cars Carrera cars? If so they might have a Carrera digital plug/chip in them and be set up for digital racing and that will cause the behavior you are seeing.

2. The blue button is a slider switch to change between having one or two power packs (wall warts). Do you get the same readings with the switch in different positions?

3. You said "Voltage at the tabs under the track (where the leads from the powerbase connect to the rails) is under 1 volt." is that when pulling the trigger (full power) ? There should be up to 16 volts only if the trigger is pulled full.

4. What controllers are you using? Do they have two black rings on the plugs (like stereo headphones) or just one? If only one those are not the correct controllers for the power base. They short circuit the track and can cause problems

5.Since you seem to know how to use a voltmeter: Check the resistance (Ohms) of the controllers. It should go up and down smoothly. Any jumps or breaks indicate there is a problem with the controller.

I might think of a few other things but the coffee hasn't kicked in yet!

 

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[Scott1707822906]

Hello Andy!

The cars, controllers, powerbase, wall transformer... everything... is from that "Le Mans Sports Cars" set.

1. The cars I am testing are the Scalextric analog Cadillac Northstar Le Mans cars from the above mentioned set. I have tested the cars on my analog PoliCar track and the track from the Le Mans set. The Scalextric set cars run as expected on the PoliCar track (I think they will benefit from a small amount of added weight near the front of the cars) but just hum and vibrate on the Scalextric powerbase. I have cleaned the rails on the Scalextric powerbase.
2. I haven't taken a voltage reading off the spade connectors with the switch in both positions -- only the single-transformer setting of the switch. I'll try the dual-transformer switch position. It's a little difficult because I could use an extra set of hands to hold the multimeter leads to the test points plus pull the trigger of the controller. I'll scrounge around for some alligator clips in the garage...
3. Yes, trigger pulled on full. It's difficult with just 2 hands but the alligator clips should make that easier.
4. They are the controllers from the set with the tip-ring-sleeve conductors on the mini phone plugs.
5. Where on the controller plug should I measure resistance? Between tip and ring? Tip and sleeve? I did disassemble a controller and make sure the wiper was making contact with the resistance windings. I sprayed a small amount of contact cleaner on the windings while it was open.

Thank you for your suggestions.

If it turns out the powerbase is faulty, what Scalextric part number should I get for a replacement analog powerbase?

--scott

[Andy P.]

Hi Scott,

Regarding point 5: I can't remember off the top of my head so I suggest using rubber bands to hold the trigger on "full blast" and test various combinations until you get a reading.

Policar is supposed to be coming out with an adapter track piece at some point. Failing that you probably could hack one up...

If you want to stick with Scalextric though the standard power base is officially: C8545

However I personally really like ARC AIR:

https://uk.scalextric.com/community/advice/app-race-control

It adds a lot of great features like timing and pace car for racing against yourself.

[Scott1707822906]

Hello Andy,

I'm trying to avoid putting money into this layout. It's for my young grandnephews.

I checked the hand controllers and they are fully functional.

Then an inspiration struck. The sound the cars were making was oddly familiar. In the USA, everyone knows the 60 Hertz hum of the main household electrical system. I measured the voltage at the track again, but this time I had the multimeter set to measure AC volts instead of DC volts. The meter immediately showed voltage peaking at around 19 volts AC with the controller trigger on full.

This tells me I've got a bad diode on the printed circuit board of the powerbase. There is no discoloration on the board so I'm going to try to identify the bad diode with the meter.

[Andy P.]

These things get banged around a lot so it could also be that something is just loose and needs resoldering...

[Scott1707822906]

The solder joints all looked "good enough" considering general made-in-China hand soldering. Probably assembled by a 9-year-old under poor lighting...

I checked the diodes this morning. D7 is definitely bad and probably D5 as well. I'll unsolder them from the board and take them to my semi-local electronics store soon -- maybe Thursday. Hopefully he has something close...

[Scott1707822906]

Follow-up:

I continue to be shocked by the poor assembly of this PC board. While desoldering the main 1N4001 diodes (D5, D6, D7, D8) I found four broken leads. I'm assuming these leads were fatigued during assembly. Although with the number and quality of jumpers and other version hacks, the broken leads might just as likely be revisions as opposed to errors.

The good news is that I'm retired so this kind of messing around with electronics is just as fun as anything else I might be doing (messing around on my boat, building cedar planter boxes, hiking around the local lakes, etc.) so cost of labor = NIL. And 1N4001 diodes are $1/dozen so... 1/4 of a Starbucks latte. Even with rampant inflation, I can manage that expense.

We will see if replacing the diodes fixes the powerbase. If it doesn't, I'll consider buying a replacement. I'll have only wasted $1...

[Andy P.]

These things seem to be created to keep people off the streets... hence why during the pandemic sales were so high!

Seriously though these things tend to go in waves.

Thousands of products will be fine and then there will be a bad batch.

I hope you get it working!

I hate throwing things out...

[Scott1707822906]

Well, I've officially given up on this C8217 powerbase.

In the last round of testing, I replaced all of the diodes. The output of the powerbase at the lugs where it connected to the track rails was 7.5 volts. When I put a car on the track, the car sort of tried to move and the red power LED dimmed like a short circuit.

One of the problems with this repair was the very poor original assembly with sloppy solder joints and 6 jumpers sloppily soldered in place. There are lots of leads left where they snipped off some diodes and it looks like maybe some burned traces.

Thank you Andy for your advise and encouragement. Unfortunately, this repair attempt was a failure.

[Andy P.]

There is the odd, rare batch that really should not have been allowed out in the wild... Seems like you may have got your hand on one.. :-(