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Changing a head ... What need to take care of ?

success - 2008-02-11 17:21

Some time ago I wrote about my mono National Panasonic RX1450.
It had low output at tape. Output with radio was Ok.
I take it apart and notice some caps were bad.
I've changed it, and the quality and level improves so much. But tt wasn't the same with all tapes. Adjusting the azimuth was not the way since all tapes used for test were orginal tapes recorded at the same azimuth position and with the same freq. response.

I took the head apart and notice that it was worned out where the tape runs, and it was worse at it's mark (the area wich reads the current side)

I took a stereo head (don't have a mono head at that moment) that matched the mechanical req. of the deck and the problem dissapears. All tapes listen quite well and loud. But as you might expect IT DOESN'T record, while IT DOES with the original head.
I know that theads are different from the electronic point of view.

The only that I've measured is the DC impedance with and ohmeter. Is this test enoguh ?. Or I need to measurethe inductance too. At what frecq ?.

The old head shields 290 ohms. The stereo head (I used the L and R coils in series in order to catch L and R tracks) shields about the twice.
Of course that will shield an impedance matching issue.

As I can't get the original, the only mono head that a found is an "Amir 888" mono head. A generic type. I've used this brand two times.
But it's a 390 ohms ....

Photo ...



Pedro.

metad - 2008-02-12 13:57

quote:
Some time ago I wrote about my mono National Panasonic RX1450.

this is a typo, right?
as i remember you posted about 5410, not a 1450.
if yes, sorry to say but the head from your box looks a bit strange, here is an original head from RF-5410 (part# WY-061),

i'm not sure, but it looks like a ferrite head, yours looks like a regular permalloy one.
probably someone has replaced it before.

btw, top of the line Technics decks of that era had the same type of the heads - HPF head, even the most expensive one - RS 9900 ($2.000 in 78-79)

success - 2008-02-12 14:44

It's a RX1450. It's a mono cassette recorder.
But the mecha it's also used stereo boxes from Panasonic. Then a stereo head most fit phisically, but not electronically.
Now it has installed an AMIR 555 head. It's a generic fix, like mabuchi motor =). It's an stereo head, so I put the coil in series to get both signal to the amplifier. But it's a mess.
How many types of heds exists and how can I adress they ... ?

Photo ....

metad - 2008-02-12 15:35

quote:
It's a RX1450. It's a mono cassette recorder.

aha, i remember your thread about RF-5410, but missed about this one.