Classic Hifi Care

My 1956 Magnavox Berkshire (TOTL mono unit with a 150 amp) has a Collaro RC-456 changer. It's the one with the removable head shell. For some reason, it gets hung up on the last couple of grooves on a record. We are talking just before the record would end and the tone are would slip into the reject cycle. It's like there is a bad spot on the record, but, there is not, and it does it on all records. Once I help it finish, it goes into reject cycle. Then the tone are picks up with a jerk and heads home. If I have three records on, the tone arm with it's jerk movement scrapes across the top record until it get high enough not to. The tone arm is set to spec's as far as tone arm height. Any suggestions? I have followed everything written in the Collaro service manual. What am I missing?

One more thing, and maybe this is normal. It has a modern stereo cartridge that I got from Gary. The original mono Shure cartridge had a bad bridge so I had to replace it. With a modern stereo cartridge one would think that a lighter tracking setting could be used? If I go anything less than 6 grams it won't track the record? Any ideas? I'm stumped!

Thank you,
Bill

Bill, the cartridge's ability to track at a certain stylus pressure and the arm's ability to trigger the end-of-record cycle are two different things. You may want to make sure you're at the original recommended spec. I haven't examined one of these changers in a long time and can't recall what kind of trip mechanism they use. I remember that the old Garrards had a little felt pad that did not have enough friction to trigger the action when the record was still playing and the arm moved very slightly each revolution. But on the lead-out groove, the higher velocity movement did trigger it. I was doing the arm-lightening thing and had the same problem you describe.

Not sure what to say about the arm-height issue.

Chris Campbel

I am certainly no expert , but I would think the original tracking force of the original cart should be followed or what ever the mfg recommendations are or were.

The original stylus pressure was 9 grams, or, at least that is what it was with the Shure cartridge. I measured it before and after installing the new cartridge. I have no idea if that was a factory or not.

As far as the tone arm height, that is factory spec. The service info states how to check that and It's right on. The problem is, once it trips at the end of the record, instead of the tone arm ​lifting straight up and then moving back to it's rest, it lifts and rips sideways until it get about 1/4 way above the record and then the rest of the movement is as it should be. Here are a few photos of the Collaro RC-456.

Bill

First off, you take great pictures! I wish I had that talent.

Second, I know absolutely nothing about a changer. But....

My suggestion would be to watch the mechanism as it runs. There has to be a tang or a doodad of some kind connected to the tone arm. My GUESS would be that maybe that "whatever" is binding somehow just before the changer cycles. Good luck......

Today I watched the changer work, I watched it a lot. While watching, I referred to the two service manuals I have. One is a Sam's for the Collaro RC-456, and the other is a genuine Collaro Conquest service manual. I realize they are not the same changer, but they do share similarities.

In the Conquest manual I found a brief mention about stylus pressure. What it said was, set pressure according to cartridge manufacture, but not to exceed 8 grams. So much for that with the Shure cartridge being set at 9 grams. Having said that, I will continue with two discoveries I found today.

I placed a record, hit reject, and it work as it should. I then watched as the record played, and, looked at the Sam's for the 456. As the tone arm approached the end of the record, it was about 1/4-1/2 inch from the end it started misbehaving. The tone arm is stuck like a bad spot on a record. By looking at the service manual I could see how things linked together. By the way, there is no mention in the Sam's if the 456 does what it is doing here's how to fix it. There is kind of a swing arm thing that is directly below the pivoting point of the tone arm and is part of the tone arm total assemble. I took my pocket screwdriver and just laid it against the swing arm thing. Low and behold, the tone arm finished the record without a hitch. It rejected and shut off. I repeated this several times just watching to see if I could see the "WHY". I found nothing catching/snagging anywhere that might prevent the tone arm from finishing the record. Operating it by hand, the tone arm moves smooth and free. I then flipped it on its side so the tone arm mechanism was up where I could easily see it. Again, I found nothing that would hinder the operation of the tone arm.

My next thought was speed. I wondered if playing a 78 would do the same thing? Off comes the LP and on goes the 78. Hit reject, record drops, tone arm sets down on record, and nothing. No sound, and the tone arm was not moving. I picked up the tone arm and moved it to the middle of the record. Here, I got music, but it was hit and miss. Hmmm....Again, I took my trusty pocket screwdriver and gently laid the tip on the tone arm. I was kind of a balancing act, so it was a minimal pressure. I was barely touching it. As soon as I did that, there was music, the record finished, it rejected, and it shut off. Ok, why? Off comes the 78 and on goes the LP. Same thing hit reject, record drops, tone arm set down and it starts to play, and I have music. The record is play just fine. So, I wait, watch, and listen. When the record gets to the magic spot the same thing happens. It's stuck in the groove. This time, I place my screwdriver on the tone arm just like I did for the 78. Again, low and behold, the record finishes the rest of the record without a hitch. It rejects, cycles, and shuts off.

So, now I'm thinking there was a reason the stylus pressure was set at 9 grams. If I want it to play a complete record, and, cycle when done, I need to set the stylus pressure to the "PLOW" position. Which makes me very uncomfortable.

Does anyone have any thoughts or ideas that can prove my theory wrong? I'm open to anything, as I really do not want to play my good records in the "PLOW" setting.

Thank you,
Bill

It seems to me that if the tone arm pressure was too low when it misbehaves, why would it not be too low at the start of the record? Could there be a burr somewhere you have overlooked?

Any possibility that tonearm wiring is binding up? How about bearings--I have a Lenco turntable that had two sets of ball bearings and they were gummed up.

Chris Campbell

I've been reading posts from the past on the "other " forum. It seems to me that mono changers sometimes required more than 12 grams of tone arm weight to cycle properly. This would be disastrous for a stereo record. Perhaps this changer will never cycle below 10 or 12 grams regardless of what you do. Some of the accoustic record players had their tone arm weight in ounces, rather than grams. 39 grams to the ounce, or thereabouts. If you lay the blade of your pocket screwdriver on the tone arm then it cycles and ends the record properly, that tells me that your issue may indeed be tone arm weight being too light. Maybe a Conquest changer, made for stereo, bridged for mono might be a reasonable consideration while maintaining a modicum of originality. Would the stereo cartridge you have now have anything to do with the tracking issue? Perhaps a combination of tone arm weight AND tracking of that stereo cartridge could be a double whammy, if you will? Just thinking out loud, and I reserve the right to be wrong......

I'm not sure, but, it is making sense to me. Just the ever so slight pressure of my pocket screw driver allowed it to finish the record and cycle properly. Which, by the way, I would never have thought of if it was not for the fact that a 78 record would not play at all without the addition of my screwdriver weight. I think I'm going to bump the stylus pressure back up to nine grams and see if it then operates as it should. I'll post my results.

Bill

I don't see where you posted the recommended tracking weight of the stereo cartridge. Will increasing tone arm weight get you into trouble there?

I did not post it, I guess I should look on Gary's site and see what it says.

I did my experiment this afternoon. I went from 6 grams to 7 and it helped but still hung up a couple of times. I laid my screwdriver on the tone arm and it finished playing the final track. I quickly removed my screwdriver and it would not follow out into reject, I laid my screwdriver back on top to complete the cycle. I increased the weight to 8 grams and it worked just fine all the way thru the record and into reject. That is were I left it until tomorrow. I'm still confused!

Does anyone out there in forum land have a Collaro RC-456? I would love to know how yours works?

Bill

It sounds like tonearm weight has something to do with it for sure. Eight grams might be a touch heavy for stereo records. Eight grams may NOT be too heavy for mono records. It will be interesting to learn what the recommended tracking weight for the stereo cartridge you used is supposed to be. You may be getting close.

Gary substituted a Pfanstiehl stereo cartridge model 228 for my original Shure mono cartridge. His, and, my thinking was lighter weight, stereo, so I would feel comfortable playing stereo records on my mono Berkshire. The Pfanstiehl recommendation for stylus weight is between 4-8 grams. I guess I'm at the top scale on that one.

Bill

I haven't messed with an RC-456 in quite a while, but it should operate just fine with a tracking force as low as 4 grams.

With the platter removed, swing the tonearm in and out, and you will see the link that trips the gear on the bottom of the turntable. That link, and all it's associated linkage, needs to be completely free to move, clean, and dry. Having oil on these parts will cause the tonearm to drag at the end of the record due to the viscousness of the oil.

The factory service literature recommends 8 to 10 grams tracking force, but in my experience this changer has no problem tracking lighter than that when all is right..

Thanks, Ken, and, to all that have made suggestions. I have checked all of the linkages but may have missed something. I need between 8 and 9 grams for it to track properly and reject at the end. The original Shure cartridge, that I am presuming is the original, was set at 9 grams. The Shure sounded fuzzy and kind of distorted, that is the reason I replaced it.

Bill