Portastudio 464 Will not play

[nicklas18]

got a unit at auction, was doing the (3) blinking lights when engaging buttons. took it apart and everything appears to be ok now. ff and rew are working, replaced the capstan belt, cleaned the gears and used lube105 - but when i press play, it will engage and then retract. what i am able to do is trip the sensor and get the play feature to work when pushing them in with my fingers. but no such luck with either of the two walmart cassettes i had laying around. and lets not talk about the record button i can't get to light up since the original 3 light fault. what did i miss? thanks in advance

 

[SkywaveTDR]

First, we do not know what model we are dealing with. Second in some mechanisms the capstan belt has nothing to do with the mechanical activation of the modes. If the Unit is a 122 Mk III the decks mechanism needs to come apart not only the back gears but also the slide plates of the front where the head base is. It is not an impossible job but may scare beginners away due to the complexity of the job. I take all slide plates off and clean all that is there no old grease is allowed to stay. Also there is a feedback PCB that has old grease on it that can lift the contact fingers off the PCB which will not give the controller proper feedback- when it is confused it goes to error mode. The Gear C in a lot of deck crack or has missing teeth- this is why I get orders of then all the time and I replace a lot of them here too.

 

[nicklas18]

it's the protastudio 464 model. so i managed to get it to play when the sensor is covered. but when i put an actual tape in it engages and then disengages the heads. the tape wont move. i assume it's because it's a cheap cassette. i cleaned the gears and did the lubriplate 105 like the tutorials state, and changed the capstan belt. so i am further along but that whole engage then disengage thing is throwing me off.

 

[SkywaveTDR]

Did you clean off the feedback plate that the cam gear contacts makes contacts to. If this has bad gummed up grease the little contacts will be isolated from the PCB.

 

[SkywaveTDR]

Part 51 in the 464 diagram is the like parts shown above which is from a 122 MkIII.

 

[nicklas18]

yes, i cleaned the old stuff off the pcb board and put new lubriplate 105 on there. all the contact points seem fine. like i said, i can get it to engage, but with a full cassette it just turns back off. when i put in the broken tape it works fine. see videos for examples of what i am talking about.

Video 1 https://youtube.com/shorts/xEClmOhL2qk?feature=share

Video 2 https://youtube.com/shorts/rU2bzySdmXE?feature=share

 

[SkywaveTDR]

The difference between the two videos is that the capstan is not running and in not doing so the rotation detection is doing it's job. Do you have a running capstan motor or too tight a belt. The motor should be running as soon as a tape is put into the well. If it does not then you have to see why that motor is not running.

 

[nicklas18]

suggestions on how to test that it's running? not to be snarky but i don't have x-ray vision, so any direction you can provide would be great. i appreciate that you've answered me and would send thank you beers.

 

[nicklas18]

figured out i need replacement EG-530KD-2B - any suggestions on where to get a decent one? i'm checking ebay now.

 

[SkywaveTDR]

I have some here and if you can not get the 2B (12Vdc) then the 9B will also work as long as you put a couple of diodes in line with the 12V + terminal. I was looking at what the difference was and it seems the max voltage data on the 9B was 11.7Vdc so just under 12V. SO most decks have around 12V in them and a Diode will drop it .7 or so but to be safe in case it goes over 12V you can put two 1N4001 diodes and they will drop it almost 1 V to allow the motor to work reliably. This using of Chinese motors is required now and then prices on E bay are ridiculous up to $79 for a $2.00 motor. I put the 9B motor in a 112B deck and it works fine. I had to put a different speed pot on the pitch control as these are different motors than the original designed ones. I have a lot of Cermet trimmers here as well as 10 turn trimmers.

 

[SkywaveTDR]

Besides the motor you should oil the capstan bearing and upper motor bearing with AMSoil and then with a speed tape and a wow and flutter meter or frequency counter to set the speed. There are two pots R1 , E2 on the Mechanism control board.

 

[nicklas18]

Replaced the motor and it appears to be working like a charm. Thanks for your help

 

[SkywaveTDR]

Good for you. At least a good ending.