How to fix inaccurate dial?

[SoundsAlike]

Alright — how do I fix a tuner where let’s say a station such as 88.5 is displayed on the tuner’s dial as somewhere closer to 90.5? The dial indicator is off by somewhere close to an inch

For years I thought this is fixed by “FM alignment” but from what I’ve recently read on FM alignment is that procedure is used to fix FM tuners doing bizarre things like no reception, bad stereo imaging, or the same channel being received at multiple spots along the dial — I’ve never had any of these problems

 

[Blue Shadow]

The positioning of the dial pointer is usually changed by moving it along the tuning cord. This is part of the standard set up for a tuner and if not locked in place with tabs bent down to hold it and/or paint/glue the dial pointer might move a bit when the tuner is used to extremes. Although the correct way to 'fix' this problem is as you say an alignment, if your pointer is off by an inch all the way down the dial, I would think the pointer has slipped on the dial cord. Gotta get in there and look around. Maybe the manual for your unit explains what you need to know to make some adjustment.

 

[SoundsAlike]

The positioning of the dial pointer is usually changed by moving it along the tuning cord. This is part of the standard set up for a tuner and if not locked in place with tabs bent down to hold it and/or paint/glue the dial pointer might move a bit when the tuner is used to extremes. Although the correct way to 'fix' this problem is as you say an alignment, if your pointer is off by an inch all the way down the dial, I would think the pointer has slipped on the dial cord. Gotta get in there and look around. Maybe the manual for your unit explains what you need to know to make some adjustment.

It's a Marantz 2230, looks to be glued in place -- probably more trouble than it's worth to get it on point

 

[dr*audio]

The correct way to do this is by adjusting the local oscillator. Some tuners have only a trim cap to adjust it, some have an inductor for the low end of the dial and a cap for the high end. You go back and forth from low to high until both are accurate. You can adjust them with 2 known stations at near the ends of the dial. You must use a non metallic tool or you will detune the circuit and in the case of an inductor you will break the ferrite core if you use a metal tool. Look in the service manual under the alignment section. It will show you the location of the adjustments. If it only has a cap you adjust it in the middle of the dial. And turn the adjustments only a tiny bit at a time! They are very sensitive.

 

[Blue Shadow]

Of course, Warren's method assumes the dial pointer is in the correct original position and hasn't moved. My method is for tuners getting new string and positioning the pointer as instructed in a service manual.

 

[gadget73]

Right, first step with a tuner alignment is mechanical alignment of the pointer. Usually its easy to see if its out of whack, just run it end to end and see where the pointer stops. The service manual should tell you what it ought to be doing.

Its not impossible that the wheel on the side of the tuning condenser has slipped on the shaft, which would throw the dial without the pointer having moved on the string. I've seen plastic wheels crack at the hub where the set screws are.

 

[steveUK]

The other thing is, when you move the dial pointer along the cord to a new position, you may find that after a few end to end turns of the tuning knob it is slightly off again. This is due to the cord having a 'tight' side and a 'slack' side each side of the tuning knob. So it's a case of making small adjustments until it is more or less correct when turned in each direction. Also, when you have reset the pointer, try 'wobbling' the tuning knob in each direction to even out the play either side of it.

 

[tarior]

dr* audio gave the correct method for aligning the pointer with the dial on a tuner that hasn't had the dial cord replaced. Typically the pointer will be affixed to the cord with bent tabs and an adhesive of some sort. Futzing with trying to separate the two is a good way to end up with a broken cord or dial pointer.

 

[steveUK]

dr* audio gave the correct method for aligning the pointer with the dial on a tuner that hasn't had the dial cord replaced. Typically the pointer will be affixed to the cord with bent tabs and an adhesive of some sort. Futzing with trying to separate the two is a good way to end up with a broken cord or dial pointer.

It's not unknown for the pointer position to somehow 'get moved' along the cord. It's not difficult for someone with a bit of patience and dexterity to carefully raise a couple of tabs, remove some glue and slide the pointer to the correct position. I've never broken a cord doing that, and I've done many. If the pointer hasn't moved - and the service manual will usually identify where it should lie when the tuning knob is turned fully towards the low frequency end of the scale - then adjusting the local oscillator is indeed the way forwards. But as I explain, depending on the circumstances, the latter is not always "the correct method" to align a pointer. It could have moved due to mechanical issues, it could have moved due to component drift.

 

[acooperblock]

Same problem with my Luxurious 1982 Luxman T-450. The dial pointer is off station. 101.1fm the pointer is positioned at 97.9fm Any hints or suggestions on how to fix or realign this seemingly simple issue?

 

[dr*audio]

Same problem with my Luxurious 1982 Luxman T-450. The dial pointer is off station. 101.1fm the pointer is positioned at 97.9fm Any hints or suggestions on how to fix or realign this seemingly simple issue?

I reiterate:
The correct way to do this is by adjusting the local oscillator. Some tuners have only a trim cap to adjust it, some have an inductor for the low end of the dial and a cap for the high end. You go back and forth from low to high until both are accurate. You can adjust them with 2 known stations at near the ends of the dial. You must use a non metallic tool or you will detune the circuit and in the case of an inductor you will break the ferrite core if you use a metal tool. Look in the service manual under the alignment section. It will show you the location of the adjustments. If it only has a cap you adjust it in the middle of the dial. And turn the adjustments only a tiny bit at a time! They are very sensitive.
Pay, I say, pay attention, son! I ain't talkin' just to hear my neck roar!

 

[painttoad]

or....if we are talking a consistent 4mhz error across the dial then there is a good chance that something has slipped over the years and there is no reason why you can't tune into a known station. loosen the pulley on the tuning gang and turn it until the dial is correctly position and tighten the pulley back down.

it's a lot safer than someone inexperienced dicking with the alignment.

let alone when you get a tuner that you have to tweak the fins on the gang or the spacing of a coil to align the bottom end.

 

[Punker X]

or....if we are talking a consistent 4mhz error across the dial then there is a good chance that something has slipped over the years and there is no reason why you can't tune into a known station. loosen the pulley on the tuning gang and turn it until the dial is correctly position and tighten the pulley back down.

it's a lot safer than someone inexperienced dicking with the alignment.

let alone when you get a tuner that you have to tweak the fins on the gang or the spacing of a coil to align the bottom end.

Partially agree. The physical alignment should be checked that you get full travel on the front-end from each end to the dial. Many dials have a tick mark on the scale where the pointer should be on the end of the scale. A 4 Mhz difference would definitely show show up at the ends and you would be able to tune in 106Mhz.

 

[dr*audio]

or....if we are talking a consistent 4mhz error across the dial then there is a good chance that something has slipped over the years and there is no reason why you can't tune into a known station. loosen the pulley on the tuning gang and turn it until the dial is correctly position and tighten the pulley back down.

it's a lot safer than someone inexperienced dicking with the alignment.

let alone when you get a tuner that you have to tweak the fins on the gang or the spacing of a coil to align the bottom end.

Every tuning cap I've seen has a flat section on the shaft, so it's impossible to turn the pulley on the shaft. In the case of physical misalignment it's easiest to move the pointer.

 

[painttoad]

Every tuning cap I've seen has a flat section on the shaft, so it's impossible to turn the pulley on the shaft. In the case of physical misalignment it's easiest to move the pointer.

that's good to know altho i have yet to see one with a flat spot on the shaft but i haven't been around as long as you guys.

 

[knockbill]

Right, first step with a tuner alignment is mechanical alignment of the pointer. Usually its easy to see if its out of whack, just run it end to end and see where the pointer stops. The service manual should tell you what it ought to be doing.

Its not impossible that the wheel on the side of the tuning condenser has slipped on the shaft, which would throw the dial without the pointer having moved on the string. I've seen plastic wheels crack at the hub where the set screws are.

This first^^^