Porta 07 fried

[silki]

Ijut bought this porta 07 for 20bucks, looks like its been trough some rough time but stilll wanna get it to work. Can someone identify this D602 diode? also, what could i put in place of Q604 transistor it says c1815 on it but cant find viable replacment.
Second problem is that tape deck, it grinds when i press play with the cassete and pulls the tape out of the cartrige but without one it spins normal, also ffwd frwd works okay..id say its the spring around that metal pole but not sure, belts are okay.

 

[Lachlan Webster]

How funny. I am in a similar predicament, having bought this last year.

I have an audio out issue.

Could you please share with me how you got the case open on yours?

This is my first time opening anything up.

 

[silki]

What I have found out is that its been messed up by polarity inversion, which means opamps are fryed too and should be replaced..
Unscrew bottom screws and the one in the deck itself at the front and it should just split in two...
Let me know if u managed to fix it

 

[Lachlan Webster]

Hey,

Yes, I came across a video about polarity inversion, too.

It was on a porta 02, but the fella seems to think that all that may be required is capacitor replacement.

I've about 6 capacitors that are noticeably blown on mine. Have ordered replacements. If that doesn't work it's off to the technological graveyard.

Here's the video if interested:

 

[silki]

Yeah, I ve seen that but i truly doubt thats tha case, as there is a thread here about porta 07 where a guy said he repaired numerous cases where polarity was inverted and said that opamps are out almost always.. Found them on ebay $3, so im planing to restore it

 

[SkywaveTDR]

These units that have gloom and doom care are repairable but the cost can get high due to the hours it takes. How do you know the Op Amps are blown? Did you measure each one with a meter? Just put sockets in and replace them it is not all that bad. In all my years I have seen mechanical problem bad motors and broken solder joints but never a burned up part like that. There was a lot of abuse done to that machine. Maybe the damage ends just at the regulator area?

 

[jo1234]

I recently bought a service manual for the porta 07. If you need some info hit me up. The Parts Q604 and D602 are a 2SC1815GR Transistor and a 12Volt zener Diod called RD12EL2.

 

[SkywaveTDR]

If you are a Technician or acting as one why don't you just look the parts up and then replace with what is compatible? These are not that hard to fix and I don't get why people are blowing them up with inverted power.
https://alltransistors.com/crsearch...&ic=0.15&tj=175&ft=80&cc=3.5&hfe=70&caps=TO92

Check these transistors but any 60V .150A Ic and 200-400 hFE transistor should work.
I have used KSC1845 transistors from Mouser in a lot of places that say they require a .150A transistor but they do not run them at anywhere near that so the KSC1845 works fine.

 

[SkywaveTDR]

RD12EL2 is just a 500mW (1/2 Watt) 12V Zener diode. Put a 1 watt in and be done with it.
https://www.mouser.com/Semiconducto...iers/Zener-Diodes/_/N-ax1mh?P=1yuq68qZ1z0z63x

Take your pick. I would use
BZX85B12-TR
But I have a lot of Zeners here already- a box of different ones.
Clean the burns carbon from around the leads of the transistor as carbon is conductive.

 

[SkywaveTDR]

Grinding can be from gears not positioning the correct way due to dried grease and I think I had to take the reel assembly apart on the bottom to find a totally stuck plastic gear and once that was freed up with old grease cleaning with denatured alcohol and Lubriplate 105 applied the deck worked like new.