Record Player - Thorn 425 Solid State Radio issues

 

New member
Username: Bacca246

Post Number: 1
Registered: Apr-11
Hi, just purchased a Thorn 425 Solid State Radio Record Player, However pretty much every record I play the stylus seems to skip through songs and the end result is that its practically unusable as a song wont play without some form of skipping through it usually it seems to glide over. I know these records are fine as I've played most of them on my friends record player and they play fine.
I've done some research and am guessing its something to do with the weighting of the needle. I've taken some pictures to show you what its like as im not sure what needs to be adjusted etc.

Any help is much appreciated as its very frustrating!

Cheers










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Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 16070
Registered: May-04
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Though you've "just purchased" this unit it doesn't appear to be a new product. That presents multiple options to select from as the reason for incorrect play. Had this unit been playing properly before you made the purchase? Are you sure of your answer? An eBay seller telling you the unit is "in perfect condition" is no indication the seller ever tried to use the player.

There is no reason for any tonearm to go out of balance while it just sits. The tonearm on your player is a static balance type which means the balance of the arm is established through purely mechanical means. Unless someone purposely moved an adjustment, there is no reason for the arm to not be properly balanced once it has been set up - even if that set up occurred twenty years ago. The arm does look to have a spring loaded downforce and, is someone has moved the dials on the arm, then readjustment might be necessary. I can't tell from your blurry pictures where the downforce might be set but simply move the dial on the side of the arm to "0". If the arm immediately sinks or rises when lifted from its rest position, then the balance is off. If it does nothing, then the basic balance is set and you just need to return the dial back to whatever location it had prior to this test.

You then need to start by knowing whether the player had been working properly before you made the purchase. Had you heard it make sound in order to validate your answer? If the answer is "no", then I would look elsewhere for the solution to your problem. Any table that has sat for any length of time can suffer from hardened grease. Your table appears to be a fully automatic table which would lead me to think the grease in the automatic mechanism has hardened and isn't allowing the arm to properly track the disc. This would require a trip to the repair shop for a complete cleaning and set up for this player. The cost will probably be around $75-100 if no parts need replacement. If the table was shippped and not packed properly, then parts could easily have been damaged in shipment and you're probably kinda screwed. The problem here is I doubt you'll find anyone who wants to touch this table. There are no "thorn" repair centers and the table is obviously out of warranty. Searching for someone who does "vintage audio repair" is your best bet here as the table is fairly generic and, if no parts are required, can possibly be set up and repaired by any competent technician.

If you know the table was operating correctly before your purchase, then you can begin by looking for any wiring that might be fouled underneath the deck. If the unit wasn't packed proplery for shipment, then its possible the automatic functions are just not in synch. With the tonearm unlocked from its rest, hold the arm lightly while you give the platter a rapid spin in the direction of normal rotation. Hold the arm along its path as it travels across to set down on the non-existent disc and do not allow the arm to set down on an open platter. Set the player's functions to "off" and repeat the process.

These are the most common problems with an automatic table that has been shipped when the arm won't track. If these don't solve your problems, then the problems have just become more severe. The next step would be to check whether a stylus exists on the cartridge. It's not uncommon for a stylus to have been worn down to nothing or to have snapped off the cantilever of the cartridge. Possibly the cantilever itself is bent by improper use. Whether a new stylus assembly exists for the cartridge that is on the table or whether you'll need to buy a new cartidge is not something I can determine from here. Many threads in the archives of this forum deal with players that will not track. I would suggest you read through the archives to find more specific solutions to your problem. Automatic table problems tend to be quite similar and repeating the same instructions with each thread is not to anyone's benefit. If you read, you'll see how to determine the existence of a stylus, how to replace a stylus assembly and how to rebalance a tonearm. I hestitate to suggest you attempt the rebalance first. The posibilities of other problems existing are too strong. And, if you've never balanced an arm before, the possibilities you'll muck up the actual process is rather high. While most automatic table problems are similar, it often requires someone with experience to actually diagnose and solve those problems. Just diving in head long without first isolating the problem to a specific area is foolhardy and all the more likely to lead to further problems that didn't exist before you began mucking around. If you read and still aren't sure where to try a solution, then I would suggest you either take the table in to a repair facility or you consider returning your new purchase.


If you have performed the necessary troubleshooting and have specific questions, I'll see what I can do.



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New member
Username: Bacca246

Post Number: 2
Registered: Apr-11
Hey there thanks so much for your help. I've done some weight adjustments with the arm etc and have narrowed down the problem more so I believe. I have found that on many records as soon as drums come into play the record will skip. Quiet melodies and guitars etc seem to play fine, but as soon as the drums kick in it will just jump around. For example Hotel California - Plays fine until the beat of drums drops. Same with a brand new record I purchased. The Decemberists - Crane Wife, into plays fine but as soon as drums it'l loose it!
Any idea what this is about? Currently i'm playing simon and garfunkel and its playing flawlessly!

Sorry about the poor quality of the photos, I've discovered there is one knob on the hand that has numbers 0-6 this is defiantly weight, there is also that block with the turn knob on it near the end and when twisting it in each direction also has weight to bring closer to the center or further back. Unsure if I need to master some kind of perfect amount for each one!
I'm still unsure about what the little circular knob does at the very back on the base of the player, it has an odd number alignment I've uploaded a photo to see if you have any idea what it may do?

Thanks again for your help it is so much appreciated!Upload
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 16071
Registered: May-04
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So you've made changes to the arm without any real idea what you're doing?



From your response I assume you've not read any other threads which might pertain to balancing the arm.




Yes, if you simply apply enough downforce on the arm by tracking the cartridge at a much higher than recommended amount, the stylus has little choice other than to stay in the groove. Why is it mistracking when the drums hit? Offhand, I would say because you've managed to really booger the arm adjustments.


"I've discovered there is one knob on the hand that has numbers 0-6 this is defiantly weight ... "

This applies downward tracking force. You need to find the recommended tracking force range for the specific cartridge that is installed in the arm. This is not a generic "set it until it grinds its way through the record". If you track the cartridge too light or too heavy, you will do damage to the disc. Tracking at the upper range of the recommended force range is better than tracking above or below that point. Find the information for your specific cartridge and use it to set the correct amount of downforce or you will damage your new and old records.


"... there is also that block with the turn knob on it near the end and when twisting it in each direction also has weight to bring closer to the center or further back. Unsure if I need to master some kind of perfect amount for each one!"


Yes, you do! If you are interested in keeping your records sounding as pristine as possible, you must set up the arm to properly track the disc. This cannot be overly stressed as a requirement for proper playback. Just fiddling with the adjustments without any idea of what you're doing or what you're changing is ridiculous. I've told you to find the instructions for setting up an arm in the archives of this forum. You've preferred to ignore that advice. I really am not in the mood to repeat and repeat the same simple instructions over and over again when they are available to anyone who will simply read.

The weight on the back of the arm is the "counterweight". It sets the "0" balance of the arm by moving toward or away from the balance point of the arm. Once the arm is established at "0", you apply downforce with the 0-6 scale.


"I'm still unsure about what the little circular knob does at the very back on the base of the player, it has an odd number alignment I've uploaded a photo to see if you have any idea what it may do?"


It sets antiskating which needs to be adjusted to a force which is similar to the specification for the tracking force of the cartridge. If it is not set properly, the arm is less likely to track well and increased record wear is likely to result from the skating effect of the arm.

More information regarding each set up procedure can be found in the archives of this section of the forum.

Do not play the table unless you are certain of the condition of the stylus. If it is worn, you will increase record damage and the arm will not track well. Once again, this cannot be overly stressed as a requirement for good performance and long record life. If you are in doubt regarding the condition of the stylus, buy a new stylus. They are quite cheap for this table and far less expensive than replacing damaged LP's.



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