Jaguar CD Issue, only plays some games

[BeefMan]

I recently picked up a broken Jaguar CD on Ebay and it's not able to play all Jaguar CD games. After a few repairs Highlander and Dragon Slayer fire right up no issue. I Can also play music CD's no issue. Unfortunately the best games like BattleMorph and Iron Soldier 2 refuse to start. The unit spins up the CD and appears to be trying to load the game for about 30 seconds before it fails and gives the disc missing error. I've tested these games in another JAgCD unit I have so I know they work.

 

So far I've replaced the laser transport and all the caps. I actually even swapped in the original laser and have the same results after I discovered adjusting the POT on the transport will get the motor/spindle turning. I'm not entirely sure the POT adjusts anything on the laser, I think it actually adjusts the pulse signal going to the motor. If you turn the POT too far one way it will prevent the motor from spinning, if you go too far the other way the motor will spin way too fast when it attempts to reverse direction to slow the CD. I've also noticed the two voltage regulators(I think that's what the are, they have fins/heatsinks attached) seem to get hotter than I think would be acceptable for a consumer device. Does anyone have any ideas on what to try next? Thanks everyone!

Edited June 5, 2018 by BeefMan

[Gummy Bear]

It plays Highlander! What more could you want?

 

(maybe it's a focus issue?)

Edited June 5, 2018 by Gummy Bear

[sh3-rg]

I know it's a simple/obvious one, but have you checked that the CD is sitting correctly? Some people whack their CDs in and press down on the spindle hub thingy and that makes the CD sit too close to the laser, so it needs prising up.

[+Stephen Moss]

Perhapse the Jaguar's transport is different but usually the only pot on the transports is on the flex circuit which is usually to adjust the power to the LASER.

Motor control is via PWM and I would not have thought a pot on the transport would have any direct effect on it as the rate of the data stream is usually the controlling factor for modulating the PWM depth which is all controlled in chip, it would be unusual to have any external adjustment. The pulse used to stop the disc spinning is usually fixed to a value large enough to stop the CD at its maximum speed, consequently it may appear bigger when the disc is spinning more slowly as it then causes the disc to spin back more in the opposite direction but should be the same every time.

 

As it plays a couple of Jag CD's and music CD's there cannot be anything fundementally wrong with it. Perhaps the discs that will not play are less reflective or just have dirt/greasy finger prints/scratches on them preventing them being read. If they are clean, unscratched glass mastered original CDs I would expect them to work baring any reflectivity issues where adjusting the LASER power may help although I would not advise it as you risk burning out the LASER.

However if they are copies on CDRs (particularly those horrible tinted ones) your are likely to have trouble with them, try copying them to a CDR that looks like a nice silver glass master CD, they should play then.

 

 

[BeefMan]

Thanks for the reply guys. I'm only passing on my observations and adjusting the pot appears to change something with the motor but I could def be wrong in what is actually happening. The motor will spin at what appears/sounds like 42x CD-ROM speeds if I turn it too far in one direction, I'll make a video to demonstrate. Maybe there is another pot somewhere else on the transport?

 

All the games I'm testing are originals except World Tour Racing but it won't read that one either. It's definitely a frustrating issue since it plays music CD's and some games without issue and my original game CD's are in great condition.

Edited June 6, 2018 by BeefMan

[WIZZARD77]

Had this same problem with mine, same games even. I bought 3 different copies of Battlemorph. I changed out the laser unit with a new Phillips unit and cured it. I see you've already done that though.

[BeefMan]

I tried a cheap $12 transport I found on ebay, looks like a knock off. It also does the same with the original laser though. I'll probably buy one more laser that from a known good source and give that a shot. Thanks for the reply!

[neo_rg]

Maybe someone can take a meter reading of the pot in its untouched working state for future reference. Sometimes blindly fiddling with them and then trying to put them back into their original position is impossible, a tiny bit out either way and the resistance value will be different. With a meter reading it'll be a whole lot easier.

[WIZZARD77]

This is what I used https://www.amazon.com/VAM1202-Mechanism-Philips-Optical-Pickup/dp/B00MW5DQW0/ref=sr_1_1?ie=UTF8&qid=1528402191&sr=8-1&keywords=VAM1202