Phonoland

Hello all,

I see some similar post, but each phono is different it seems. I am absolutely a dunce at things electronic but would like to get this early Transistorized Magnavox portable going right. It sounds fuzzy on both speakers at peaks and with large instrumentations. Does same on either needle so I am told most likely the cartridge.

I wrote needle daddy with what I could make out of the serial number which appears to be 1 SC 241 run 1. He said it took at 56031 cartridge but when I finally figured out how to drop the cartridge in it, it is marked 427 on the side with a 340 1 on the top metal holder plate. So not sure what I have. But I need a replacement with needle. Any thoughts there..

Then the changer which works fair, seems to be a hair noisy no doubt due to age or oiling, wants to miss rejecting at times and falls off the record at the beginning once in a while. Again maybe oil and old grease issues mostly? If so is there anywhere where it shows you how to carefully and successfully remove the turn table and clean and grease it for dummies?
I have not shops anywhere around here that are even inclined, or mostly not inclined, to want to service anything beyond a MP3 era item.

thanks

The best book you can get on record changer repair is Servicing Record Changers, by Harry Mileaf. It explains the mechanical parts of record changers like no other book. I see it on eBay every few weeks.

Several different companies make cartridges, so the numbers you have might be an equivalent replacement part. But, before you worry about replacement, check the tracking force. If it is wrong, the sound you heard is the result, and the records will wear.

Most of the early Micromatics take a tracking force between 3 and 5 grams equivalent force. A stylus force gage is a must for setting the stylus force.

Most of the problems you cite are due to adjustments or dirt.

The location of the adjustments depends on which Micromatic you have:

Original Micromatic - looks like my avatar (without the modifications I added), three control knobs:
- Pickup arm raising height: Hole in top of the arm, over the arm shaft. Adjust for proper size scanning height.
- Record size setdown: On change cycle cam, accessed through a hole in the turntable under the mat.
- Stylus force: Hole at the rear end of the tonearm. Clockwise reduces force.
- This unit does make some sounds during the change cycle. Some units also have no rubber motor mounts.
- A variant version has two concentric controls instead of three knobs.

1962-1964 Micromatic - Front of arm looks like a snake head, sickle-shaped overarm tip, two concentric controls:
- Pickup arm raising height: Hole in top of the arm, over the arm shaft. Adjust for proper size scanning height.
- Record size setdown: On plinth between arm shaft and turntable.
- Stylus force: Hole at the rear end of the tonearm. Clockwise reduces force.

1964-1966 Micromatic - Arm is squared off, fishhook-shaped overarm, two concentric controls:
- Pickup arm raising height: Hole in plinth behind pickup arm shaft. Adjust for proper size scanning height.
- Record size setdown: On plinth between arm shaft and turntable.
- Stylus force: Thumbscrew under rear of tonearm. Clockwise reduces force.

1967 and newer Micromatic - Various arm styles, fishhook-shaped overarm, 3-size index, two controls:
- Pickup arm raising height: Hole in plinth between pickup arm and overarm. Adjust for size scanning height.
- Record size setdown: On right side of tonearm just behind arm shaft.
- Stylus force: Thumbscrew under rear of tonearm. Clockwise reduces force.

The arm raising height must be set so the arm does not touch the records on the spindle when swinging out, but does touch the records when scanning for size.

The changer must be out of cycle when the record size adjustment is made. It is a process of trial and error.

Start by turning adjustments small amounts (1/10 of a turn). They are quite sensitive, especially the record size setdown adjustment (half a turn is the entire range of adjustment).

The cause of improper tripping in all of these is one of the following:
- Dirt, oil, or grease in the trip parts. They must be clean and unlubricated to work.
- The changer is not level. The trip mechanism operated by gravity.
- Damaged parts
- No finishing groove on the record.

- Note that if record sizes are intermixed, they must be stacked in pyramid fashion, with larger records below smaller records. If they are stacked on any other order, the arm will set down at the wrong place.

- Note that some 12" RCA records ("Dynaflex") made in the 1960s and 1970s will cause the pickup to slip off the edge of the record when the setdown is adjusted to work with all other records. These records were not made to industry standards, in order to save vinyl. Adjusting the setdown to work with these records causes the pickup to set into the music on other records.

Thanks a lot,

The information was worth the wait.. Things a bit slow here at times.

Here is what I have been forced to figure out, with a few tips similar to yours. "Dirt" can be a real issue and one I wouldn't have guessed would cause quite the problem it does. I was looking to change the needle and the cartridge but having not much luck. I had dropped the cartridge down to observe the number and when I replaced it it seemed to sound a hair better. Then I Had an issue with a needle on a GE Slimline yesterday and discovered how much the needle could cause troubles. I finally got a needle in it that sounded clear, but the one I purchased that was supposed to fit the GE didn't as it was not shaped correctly on the tip. It was straight out where the original was bent in several directions towards the tip.

Anyway back to the Maganavox. After I realized how much effect the needle had, I decided to see if I could remove the Maganavox one and check for a new one.. When I removed it I noticed a bit of "fuzz" on the rear where it snaps into the arm under the spring. I took a tooth brush with a bit of alcohol on it to the whole needle, cleaning it well. Then I blew out the rear under the cartridge.. The thing now sounds just about like New.. Who would have thought it. I had recalled seeing someone post on another site that dirt could be one of the issues that caused the problem I was describing.. Good thing I didn't buy a new cartridge, it apparently doesn't need one. Now I have the service to the turntable issues which give me more pause about getting into it.

Your post is wonderful in its depth of information and I appreciate the tip on the book. Not sure I could follow a book of that nature, but maybe.

What I am still not really clear on is in those screw adjustments you mention I am not sure which one is the one that determines how far into the record the needle sits down? Unless I am wrong the only two screws I see that might adjust the arm from above the turntable are two, one of which I just now found. The one I hadn't noticed is a small screw set into the motor board about a inch behind the pivot and about a half inch from the edge of the motor board. I have not turned that one as yet. The other is about an inch an a half in front of the pivot point and in a similar location. Its a bit larger screw. I see no screws or openings in the top of the arm anywhere? The arm does look like a snake head, sort of resembles the old Zenith Cobra Arm.

The machine is not rejecting many 45's and yet on 33 speed records it seems to trip? What little reading I have done around the web that seems to be a dirt issue or old grease perhaps also? You say no lubrication on the lower parts, is that right? I thought I read where light grease under the sliding pieces was what they needed?

thanks again, hope you can respond.

larryh wrote:Thanks a lot,

Anyway back to the Maganavox. After I realized how much effect the needle had, I decided to see if I could remove the Maganavox one and check for a new one.. When I removed it I noticed a bit of "fuzz" on the rear where it snaps into the arm under the spring. I took a tooth brush with a bit of alcohol on it to the whole needle, cleaning it well. Then I blew out the rear under the cartridge.. The thing now sounds just about like New.. Who would have thought it. I had recalled seeing someone post on another site that dirt could be one of the issues that caused the problem I was describing.. Good thing I didn't buy a new cartridge, it apparently doesn't need one. Now I have the service to the turntable issues which give me more pause about getting into it.

Sometimes a needle can get cockeyed in its mount.

Your post is wonderful in its depth of information and I appreciate the tip on the book. Not sure I could follow a book of that nature, but maybe.

What I am still not really clear on is in those screw adjustments you mention I am not sure which one is the one that determines how far into the record the needle sits down? Unless I am wrong the only two screws I see that might adjust the arm from above the turntable are two, one of which I just now found.

The one I hadn't noticed is a small screw set into the motor board about a inch behind the pivot and about a half inch from the edge of the motor board. I have not turned that one as yet.

Raising height.

The other is about an inch an a half in front of the pivot point and in a similar location. Its a bit larger screw. I see no screws or openings in the top of the arm anywhere? The arm does look like a snake head, sort of resembles the old Zenith Cobra Arm.

Setdown position.

I now know which unit you have. It is a revision of the snake-head machine I have.

The machine is not rejecting many 45's and yet on 33 speed records it seems to trip? What little reading I have done around the web that seems to be a dirt issue or old grease perhaps also? You say no lubrication on the lower parts, is that right? I thought I read where light grease under the sliding pieces was what they needed?

First, check the records. There are a few 45s that do not trip on mine. Their finishing grooves move in less than 1/8 inch. My copy of the Beatles "Hey Jude" is one of them. It won't trip if the record is in a certain position in relation to the turntable.

The trip depends on an increase in velocity of the arm. The trip finger is the lower of the two fingers on the arm shaft assembly. It fits into a slot in the trip arm (located under the change cycle cam, as viewed when the changer is right side up). The trip striker arm rests on top of the other end of the trip arm, and is moved by the trip arm toward the turntable hub.

Once per turntable rotation, the rotating striker on the turntable hub touches the striker arm. If the pickup is playing the music, the striker arm moves just a little. So the striker pushes the striker arm back just a little. Because the striker arm is resting on top of the trip arm by gravity alone, the trip arm is not affected by this motion.

But if the arm has entered the finishing groove, the striker arm moves a lot toward the turntable hub. This time, the striker on the turntable hub latches the striker arm and drives it in a direction perpendicular to the trip arm motion. This moves the drive wheel crank, unlatching it and starting the change cycle.

If there is grease or oil on the striker arm pivot, it will retard the striker arm, keeping the trip arm from moving it in unless the trip arm moves a large distance. This keeps the change cycle from starting.

Grease on the other trip parts will hinder the motion of the pickup arm, increasing record wear and possibly causing the stylus to jump grooves. It is possible that the changer is not tripping because the stylus is jumping out of the finishing grooves. (Misadjusted height can also cause this to happen on the first record.)

Note that the pivot of the drive wheel crank is lubricated, but not the pivot of the striker arm on the drive wheel crank.

If the finishing groove on the record moves the arm less than 1/8", the striker could reset the striker arm in the middle of this motion, if the record is placed on the turntable so the stylus is halfway through the leadout motion when the striker hits. This keeps the changer from tripping. Turning this kind of record 180 degrees on the turntable will make it trip. Note that a record of this kind was not made to standards, which requires the leadout groove to move at least 1/4" per turntable rotation, and to keep moving in for at least one rotation.

If the trip arm is bent so the curved end the striker arm rests on is sloped away from the spindle, the striker arm will slide down it and not trip the changer. If it is bent the other way, the change cycle will start too soon. If the changer is not level, the same effects can happen.