rockola

Hi
I sill can't get this rockola to select from the correct record slot in the basket, no matter how i adjust the read out arm. When you select the first record A1, it always selects the next record C1 or in between the A1 and C1, this repeats itself more or less to the very last record, whereby if you select any record the basket stops at the next record slot (which is the next slot after the selected one) or sometimes just slightly between them, this is my final problem with the machine and would be great to get it sorted out, have never seen this happen before on any of the electro-mechanical Rockola's. Can the basket itself be adjusted or rotated independently without affecting the read out arm,
clones

The only thing I can think of is the dynamic brake is failing (motor is "coasting")--check both the electrical, and mechanical action of the release and trip relays in the junction box--there is "no adjustment" other than that which you have already "played with" on the read out arm-- Ron Rich

thanks, i'll check this out
regards
clones

Did you find the problem ?

Some extra info for you

Agreeing with Ron, it sounds very much like dynamic braking.

I assume you are referring to the search (or write-in) motor stopping at A1 C1 or somewhere in between.

If so there will be a braking circuit. I have not looked at a 437 but certainly on the later rockolas, this is performed by briefly connecting the AC write-in motor
to the 28V dc rail through a currently limiting lamp (in the PSU). This was a problem that I encountered when I restored my 474.
The lamp holder had fallen apart. I repaired the holder and also soldered directly to the bulb for good measure.
Obviously check the lamp (or resistor etc) first.

Pete

Hi
The write in is tripping the correct selection lever, but the basket doesn't stop at the correct postion, for example when A1 is selected the basket brakes and C1 is selected and so on the whole way up through the complete record listings but there are some exceptions but these are random, the adjustment on the read out arm won't adjust for that amount spacing, the interlock as far as i can tell is operating correctly, however the motors in this machine are 23 volt motors and the power supply is giving out 28 volts dc, the gripper arm moves a bit quicker than normal compared to other later rockolas that I have, so i wonder is it possible that the basket motor is moving too quickly and not braking correctly, i have read previously in alwaysjukin that a 20 ohn 20 wattt resistor can be in the power line to reduce the 28 volts down to a suitable voltage for the 23 voly motors to operate
regards
clones

"--23 volt motors--" ? Are you sure, that you are just not mis-reading the 28 volt, as 23 ?..
I have never noticed that--?? Ron Rich

they are marked as 23 volts dc, i presume they are similar to the 22 volt motors that are in later rockolas such as the rockola 451 and 464 which i currently have
regards
clones

By any chance, did you look at the schematic ? What is the voltage used to drive them ?
Ron Rich

I did yes, they are ran by 28 volts dc

Just guessing--you are misreading the motor--bet that "3" is really an "8" ----???
BTW--the scan motor also uses a "dynamic brake"---I am not so sure about the WI, AC motor, as I thought it used a clutch drive-
Ron Rich

Hi

Since the WI selection is always correct, it confirms that the brake on the AC WI motor I mentioned earlier appears to be ok.

If your magazine is not stopping consistently on the correctly selected pin, then as Ron has said there could be a problem with the braking circuit
for this motor.

Looking at the diagram for my later Rockola (which also uses the 28V DC motors) a dynamic brake is applied by shorting the motor's winding via the interlock relay in the control box.

As soon as the interlock relay is tripped (via the read-out carriage contacting the selected pin on the pin bank), power is removed from the magazine motor and a short is applied across it, this is done by the same contacts on the interlock relay.

You might like to try checking the contacts on this relay.

Also of course, check that you don't have excessive play in the gearing to the magazine.

Pete

thanks, will do, its a problem i haven't come across before
regards
clones

Hi
Just thought i would let you all know that i cleaned thoroughly the interlock relay contacts and it has rectified the situation, along with some minor bending of the some of the record dividers. The previous owner must have did something to them as the gaps were different widths at some of the selections, thanks again
regards
clones

Glad you got it !--and thanks for the post--- Ron Rich