Hello All,
I hope it's ok to talk about this "45" turntable attachment. It did attach to radios used in the 40s and 50s.
I cannot get the damping mechanism to work right. I cleaned the piston and the cylinder but there's no way to get it to slide as easily as on another RP-168 turntable I have. But this may have worked with the weight of the original cartridge but not with lighter 81T cartridge. It's just not enough weight to over come the damping. I tried a penny or nickel on the arm. They were heavy enough to over come the damping but it was so heavy that it made the needle gouge and ruin the record. Removing the counter balance spring had the same result. The damping would work normally but the record would be ruined and excessive pressure would bend the stylus. So I had two choices 1: remove the damping piston or 2) increase the weight and allow the needle to gouge the record and bend the stylus. So I chose to remove the piston part. The record drops fast but it seems to work and sound great. I think the 81T was pretty rugged. It was used in school phonos. So I think it will be ok.
Has anyone else had this problem? Does what I did sound ok to do?
Is there another solution to this problem?

Thanks,

Dave

If that is the RP 168 with it being a little stand alone 45 RPM player, I don't remember any electro mechanical damping being involved on that unit. E.G ,
Supposedly, much in the order of a piston ...or felt… or leathered units on others....within a sleeved cylinder and the controlled leakage of air from a "weep" hole ..or around the losely fitted “piston” producing the dampening effect.

Consult the accompanying photos of the units topside and tone arm lift mechanism bottom sides and compare.

http://img267.imageshack.us/img267/8130/45mechtopsidelr8.jpg
http://img238.imageshack.us/img238/2999/rp168ry1.jpg

The tone arm (9) needed a free play swinging upwards and downwards from set/ pivot screw (8).No friction within support sleeve (24D) presented to passing thru
tone arm shaft (12) from old caked/ dried out/ glazed lube residue ..right?. It has to freeeeely rotate as well as its being lifted. The basic tone arm /cartridge weight …cumulatively establishing the tracking force, being established by spring (10). Plus the tone arm propers weight and the front mounted crystal cartridge ..[and HOW many of them can still even have any voltage output]...having been replaced.

Sooooo if you have an appreciably lighter replacement cartridge and could not reinstate proper tracking weight by making proper spring re-adjustment. And that can be tricky and somewhat unreversible. You would be better off on accruing incremental weighting adjustments with the experimental placemant of a larger weight back just in front of the pivot point at (8). When you are putting a weight way up front of the tone arm at the top of the cartridge area , you are additionally upsetting the lateral swing mass of the tone arm. That correct...ive / ing positioning waaaay back near the pivotal point, will have less effect on the tone arms rotational mass.Of course that will be a heavier weighting as compared to the penny or nickel atop the cartridge position.Plenty of room is under the U channel of the rear of the tone arm for its final location after an initial optimum value is established topside.

The bottom changer pic was just showing the lift action that was put on the tone arm via elements (19 )and (24E ) during the change cycle.

73's de Edd

Edd,

In the diagram and the picture part number 19 (45mechtopsidelr8.jpg), on the two turntables I have, the part extends to the left end There is a hole near the end that connects to a wire that's attached to a piston, that moves inside a cylinder. This piston/cylinder is nowhere in any of the service data I could find, yet it's in BOTH of the 45J turntables I have in front of me. This is wierd. The service data covers the RP-168. Maybe the 45J/RP-168 is slightly different. But, I can guess why RCA eliminated this feature in later models off RP-168s. So maybe it was a good idea to remove the piston.

Thanks,

Dave
:If that is the RP 168 with it being a little stand alone 45 RPM player, I don't remember any electro mechanical damping being involved on that unit. E.G ,
:Supposedly, much in the order of a piston ...or felt… or leathered units on others....within a sleeved cylinder and the controlled leakage of air from a "weep" hole ..or around the losely fitted “piston” producing the dampening effect.
:
:Consult the accompanying photos of the units topside and tone arm lift mechanism bottom sides and compare.
:
:http://img267.imageshack.us/img267/8130/45mechtopsidelr8.jpg
:http://img238.imageshack.us/img238/2999/rp168ry1.jpg
:
:The tone arm (9) needed a free play swinging upwards and downwards from set/ pivot screw (8).No friction within support sleeve (24D) presented to passing thru
:tone arm shaft (12) from old caked/ dried out/ glazed lube residue ..right?. It has to freeeeely rotate as well as its being lifted. The basic tone arm /cartridge weight …cumulatively establishing the tracking force, being established by spring (10). Plus the tone arm propers weight and the front mounted crystal cartridge ..[and HOW many of them can still even have any voltage output]...having been replaced.
:
:Sooooo if you have an appreciably lighter replacement cartridge and could not reinstate proper tracking weight by making proper spring re-adjustment. And that can be tricky and somewhat unreversible. You would be better off on accruing incremental weighting adjustments with the experimental placemant of a larger weight back just in front of the pivot point at (8). When you are putting a weight way up front of the tone arm at the top of the cartridge area , you are additionally upsetting the lateral swing mass of the tone arm. That correct...ive / ing positioning waaaay back near the pivotal point, will have less effect on the tone arms rotational mass.Of course that will be a heavier weighting as compared to the penny or nickel atop the cartridge position.Plenty of room is under the U channel of the rear of the tone arm for its final location after an initial optimum value is established topside.
:
:The bottom changer pic was just showing the lift action that was put on the tone arm via elements (19 )and (24E ) during the change cycle.
:
:
:73's de Edd
:

Edd,
There's no friction at all the 19 moves very freely when not attached to the piston.

Dave
:Edd,
:
: In the diagram and the picture part number 19 (45mechtopsidelr8.jpg), on the two turntables I have, the part extends to the left end There is a hole near the end that connects to a wire that's attached to a piston, that moves inside a cylinder. This piston/cylinder is nowhere in any of the service data I could find, yet it's in BOTH of the 45J turntables I have in front of me. This is wierd. The service data covers the RP-168. Maybe the 45J/RP-168 is slightly different. But, I can guess why RCA eliminated this feature in later models off RP-168s. So maybe it was a good idea to remove the piston.
:
:Thanks,
:
:Dave
::If that is the RP 168 with it being a little stand alone 45 RPM player, I don't remember any electro mechanical damping being involved on that unit. E.G ,
::Supposedly, much in the order of a piston ...or felt… or leathered units on others....within a sleeved cylinder and the controlled leakage of air from a "weep" hole ..or around the losely fitted “piston” producing the dampening effect.
::
::Consult the accompanying photos of the units topside and tone arm lift mechanism bottom sides and compare.
::
::http://img267.imageshack.us/img267/8130/45mechtopsidelr8.jpg
::http://img238.imageshack.us/img238/2999/rp168ry1.jpg
::
::The tone arm (9) needed a free play swinging upwards and downwards from set/ pivot screw (8).No friction within support sleeve (24D) presented to passing thru
::tone arm shaft (12) from old caked/ dried out/ glazed lube residue ..right?. It has to freeeeely rotate as well as its being lifted. The basic tone arm /cartridge weight …cumulatively establishing the tracking force, being established by spring (10). Plus the tone arm propers weight and the front mounted crystal cartridge ..[and HOW many of them can still even have any voltage output]...having been replaced.
::
::Sooooo if you have an appreciably lighter replacement cartridge and could not reinstate proper tracking weight by making proper spring re-adjustment. And that can be tricky and somewhat unreversible. You would be better off on accruing incremental weighting adjustments with the experimental placemant of a larger weight back just in front of the pivot point at (8). When you are putting a weight way up front of the tone arm at the top of the cartridge area , you are additionally upsetting the lateral swing mass of the tone arm. That correct...ive / ing positioning waaaay back near the pivotal point, will have less effect on the tone arms rotational mass.Of course that will be a heavier weighting as compared to the penny or nickel atop the cartridge position.Plenty of room is under the U channel of the rear of the tone arm for its final location after an initial optimum value is established topside.
::
::The bottom changer pic was just showing the lift action that was put on the tone arm via elements (19 )and (24E ) during the change cycle.
::
::
::73's de Edd
::

Dave,
You can make small incremental weight adjustments using small snipets of lead based solder, and once you arrive at the correct number (weight), melt into a small pod to attach under the arm.

marv

:Edd,
: There's no friction at all the 19 moves very freely when not attached to the piston.
:
:Dave
::Edd,
::
:: In the diagram and the picture part number 19 (45mechtopsidelr8.jpg), on the two turntables I have, the part extends to the left end There is a hole near the end that connects to a wire that's attached to a piston, that moves inside a cylinder. This piston/cylinder is nowhere in any of the service data I could find, yet it's in BOTH of the 45J turntables I have in front of me. This is wierd. The service data covers the RP-168. Maybe the 45J/RP-168 is slightly different. But, I can guess why RCA eliminated this feature in later models off RP-168s. So maybe it was a good idea to remove the piston.
::
::Thanks,
::
::Dave
:::If that is the RP 168 with it being a little stand alone 45 RPM player, I don't remember any electro mechanical damping being involved on that unit. E.G ,
:::Supposedly, much in the order of a piston ...or felt… or leathered units on others....within a sleeved cylinder and the controlled leakage of air from a "weep" hole ..or around the losely fitted “piston” producing the dampening effect.
:::
:::Consult the accompanying photos of the units topside and tone arm lift mechanism bottom sides and compare.
:::
:::http://img267.imageshack.us/img267/8130/45mechtopsidelr8.jpg
:::http://img238.imageshack.us/img238/2999/rp168ry1.jpg
:::
:::The tone arm (9) needed a free play swinging upwards and downwards from set/ pivot screw (8).No friction within support sleeve (24D) presented to passing thru
:::tone arm shaft (12) from old caked/ dried out/ glazed lube residue ..right?. It has to freeeeely rotate as well as its being lifted. The basic tone arm /cartridge weight …cumulatively establishing the tracking force, being established by spring (10). Plus the tone arm propers weight and the front mounted crystal cartridge ..[and HOW many of them can still even have any voltage output]...having been replaced.
:::
:::Sooooo if you have an appreciably lighter replacement cartridge and could not reinstate proper tracking weight by making proper spring re-adjustment. And that can be tricky and somewhat unreversible. You would be better off on accruing incremental weighting adjustments with the experimental placemant of a larger weight back just in front of the pivot point at (8). When you are putting a weight way up front of the tone arm at the top of the cartridge area , you are additionally upsetting the lateral swing mass of the tone arm. That correct...ive / ing positioning waaaay back near the pivotal point, will have less effect on the tone arms rotational mass.Of course that will be a heavier weighting as compared to the penny or nickel atop the cartridge position.Plenty of room is under the U channel of the rear of the tone arm for its final location after an initial optimum value is established topside.
:::
:::The bottom changer pic was just showing the lift action that was put on the tone arm via elements (19 )and (24E ) during the change cycle.
:::
:::
:::73's de Edd
:::

Marv,
None of the later models of the RP-168 seem have this damping piston and cylinder, and the picture of the arm lifter piece in the service data doesn't have the extra section with the hole in it for a wire from the damping piston, as it is in the 45J RP-168. I can't find it in any of the RCA, SAMs or RCA service data at all. So evidently this damping feature was eliminated because of the problems with it. The changer works fine with the piston removed entirely. Any additional weight on the tone arm is too much for the 81T cartridge and it gouges the record groves. It must have the counter balance spring attached or it's also too heavy and gouges the record. I think it's fine the way it is. It cycles really fast and lands perfectly at the begining of each and every record. It picks up the arm at exactly the correct section of the record and the record drop and arm are timed perfectly. So I don't want to mess it up. I think it's fantastic.

Thanks for all the help and advice,

Dave

:Dave,
:You can make small incremental weight adjustments using small snipets of lead based solder, and once you arrive at the correct number (weight), melt into a small pod to attach under the arm.
:
:marv
:
::Edd,
:: There's no friction at all the 19 moves very freely when not attached to the piston.
::
::Dave
:::Edd,
:::
::: In the diagram and the picture part number 19 (45mechtopsidelr8.jpg), on the two turntables I have, the part extends to the left end There is a hole near the end that connects to a wire that's attached to a piston, that moves inside a cylinder. This piston/cylinder is nowhere in any of the service data I could find, yet it's in BOTH of the 45J turntables I have in front of me. This is wierd. The service data covers the RP-168. Maybe the 45J/RP-168 is slightly different. But, I can guess why RCA eliminated this feature in later models off RP-168s. So maybe it was a good idea to remove the piston.
:::
:::Thanks,
:::
:::Dave
::::If that is the RP 168 with it being a little stand alone 45 RPM player, I don't remember any electro mechanical damping being involved on that unit. E.G ,
::::Supposedly, much in the order of a piston ...or felt… or leathered units on others....within a sleeved cylinder and the controlled leakage of air from a "weep" hole ..or around the losely fitted “piston” producing the dampening effect.
::::
::::Consult the accompanying photos of the units topside and tone arm lift mechanism bottom sides and compare.
::::
::::http://img267.imageshack.us/img267/8130/45mechtopsidelr8.jpg
::::http://img238.imageshack.us/img238/2999/rp168ry1.jpg
::::
::::The tone arm (9) needed a free play swinging upwards and downwards from set/ pivot screw (8).No friction within support sleeve (24D) presented to passing thru
::::tone arm shaft (12) from old caked/ dried out/ glazed lube residue ..right?. It has to freeeeely rotate as well as its being lifted. The basic tone arm /cartridge weight …cumulatively establishing the tracking force, being established by spring (10). Plus the tone arm propers weight and the front mounted crystal cartridge ..[and HOW many of them can still even have any voltage output]...having been replaced.
::::
::::Sooooo if you have an appreciably lighter replacement cartridge and could not reinstate proper tracking weight by making proper spring re-adjustment. And that can be tricky and somewhat unreversible. You would be better off on accruing incremental weighting adjustments with the experimental placemant of a larger weight back just in front of the pivot point at (8). When you are putting a weight way up front of the tone arm at the top of the cartridge area , you are additionally upsetting the lateral swing mass of the tone arm. That correct...ive / ing positioning waaaay back near the pivotal point, will have less effect on the tone arms rotational mass.Of course that will be a heavier weighting as compared to the penny or nickel atop the cartridge position.Plenty of room is under the U channel of the rear of the tone arm for its final location after an initial optimum value is established topside.
::::
::::The bottom changer pic was just showing the lift action that was put on the tone arm via elements (19 )and (24E ) during the change cycle.
::::
::::
::::73's de Edd
::::

Hello Again,
I meant to say the RCA, SAMs and Riders RP-168 service data that I could find, didn't mention or or show a picture of the damping mechanism in the RCA 45J RP-168 changer. If someone has that service data that shows the elongated arm lifter part, and the damping piston and cylinder, I would be very interested in taking a look at it.
Maybe that service data also has a troubleshooting guide for the damping mechanism. This 45J must be one of the very first 45 changers, possibly from 1948.

Thanks,

Dave
:Marv,
: None of the later models of the RP-168 seem have this damping piston and cylinder, and the picture of the arm lifter piece in the service data doesn't have the extra section with the hole in it for a wire from the damping piston, as it is in the 45J RP-168. I can't find it in any of the RCA, SAMs or RCA service data at all. So evidently this damping feature was eliminated because of the problems with it. The changer works fine with the piston removed entirely. Any additional weight on the tone arm is too much for the 81T cartridge and it gouges the record groves. It must have the counter balance spring attached or it's also too heavy and gouges the record. I think it's fine the way it is. It cycles really fast and lands perfectly at the begining of each and every record. It picks up the arm at exactly the correct section of the record and the record drop and arm are timed perfectly. So I don't want to mess it up. I think it's fantastic.
:
:
:Thanks for all the help and advice,
:
:Dave
:
::Dave,
::You can make small incremental weight adjustments using small snipets of lead based solder, and once you arrive at the correct number (weight), melt into a small pod to attach under the arm.
::
::marv
::
:::Edd,
::: There's no friction at all the 19 moves very freely when not attached to the piston.
:::
:::Dave
::::Edd,
::::
:::: In the diagram and the picture part number 19 (45mechtopsidelr8.jpg), on the two turntables I have, the part extends to the left end There is a hole near the end that connects to a wire that's attached to a piston, that moves inside a cylinder. This piston/cylinder is nowhere in any of the service data I could find, yet it's in BOTH of the 45J turntables I have in front of me. This is wierd. The service data covers the RP-168. Maybe the 45J/RP-168 is slightly different. But, I can guess why RCA eliminated this feature in later models off RP-168s. So maybe it was a good idea to remove the piston.
::::
::::Thanks,
::::
::::Dave
:::::If that is the RP 168 with it being a little stand alone 45 RPM player, I don't remember any electro mechanical damping being involved on that unit. E.G ,
:::::Supposedly, much in the order of a piston ...or felt… or leathered units on others....within a sleeved cylinder and the controlled leakage of air from a "weep" hole ..or around the losely fitted “piston” producing the dampening effect.
:::::
:::::Consult the accompanying photos of the units topside and tone arm lift mechanism bottom sides and compare.
:::::
:::::http://img267.imageshack.us/img267/8130/45mechtopsidelr8.jpg
:::::http://img238.imageshack.us/img238/2999/rp168ry1.jpg
:::::
:::::The tone arm (9) needed a free play swinging upwards and downwards from set/ pivot screw (8).No friction within support sleeve (24D) presented to passing thru
:::::tone arm shaft (12) from old caked/ dried out/ glazed lube residue ..right?. It has to freeeeely rotate as well as its being lifted. The basic tone arm /cartridge weight …cumulatively establishing the tracking force, being established by spring (10). Plus the tone arm propers weight and the front mounted crystal cartridge ..[and HOW many of them can still even have any voltage output]...having been replaced.
:::::
:::::Sooooo if you have an appreciably lighter replacement cartridge and could not reinstate proper tracking weight by making proper spring re-adjustment. And that can be tricky and somewhat unreversible. You would be better off on accruing incremental weighting adjustments with the experimental placemant of a larger weight back just in front of the pivot point at (8). When you are putting a weight way up front of the tone arm at the top of the cartridge area , you are additionally upsetting the lateral swing mass of the tone arm. That correct...ive / ing positioning waaaay back near the pivotal point, will have less effect on the tone arms rotational mass.Of course that will be a heavier weighting as compared to the penny or nickel atop the cartridge position.Plenty of room is under the U channel of the rear of the tone arm for its final location after an initial optimum value is established topside.
:::::
:::::The bottom changer pic was just showing the lift action that was put on the tone arm via elements (19 )and (24E ) during the change cycle.
:::::
:::::
:::::73's de Edd
:::::