Re: About the Datassette update

From: William Levak (wlevak_at_cyberspace.org)
Date: 2003-03-20 05:57:47

I do have a schematic that I have labeled NP-090B.  It is probably on
funet, but may not be labeled as NP-090B.  It uses one quad op-amp
(AN-6562) instead of two dual op-amps (AN6564). They are functionally the
same.  The changes would be applied to both versions.  
The only differences I see are:
      NP-090         NP-090B
IC2-1 pin 3        IC1-4 pin 12
          2                  13
          1                  14
IC2-2 pin 5        IC1-3 pin 10
          6                  9
          7                  8

These circuits are very noisy and someone may have changed the resistors
and capacitors to improve the quality of the signal.  I know people who
have done this, but they know more about recorder circuits than I do.


On Wed, 19 Mar 2003, Daniele Gratteri wrote:

> ----- Original Message -----
> From: "William Levak" <wlevak@cyberspace.org>
> To: "CBM Hackers" <cbm-hackers@cling.gu.se>
> Sent: Wednesday, March 19, 2003 5:37 AM
> Subject: Re: About the Datassette update
> 
> > There is a 1984 Techtopics that list changes to the board.  It should be
> > on funet somewhere.  C4 is changed to 470pF and C9 (.0033uF) is added
> > across R1 and R2.
> 
> I know, it is the one in the link I posted. But, how can I identify the
> resistors? There's written nothing on the PCB... I downloaded a schematic
> and I think I have found the right resistors but they are connected
> differently to the AN6562: could it be because my PCB is the NP-090B while
> the schematic refers to the NP-090?
> 
> My NP-090B PCB uses two AN6562 op. amp. and a 74LS14.
>       __                                                  ____
>      /// Daniele Gratteri, Italian Commodore-Amiga user  / ___|____
> __  /// E-MAIL: daniele_gratteri@inwind.it   RITMO S75  | |   |___/
> \\\/// Nickname: FIAT1100D - ICQ: 53943994    FOREVER!  | |___|___\
>  \/// URL: http://spazioinwind.libero.it/danielegratteri \____|
> 
> 
>        Message was sent through the cbm-hackers mailing list
> 


       Message was sent through the cbm-hackers mailing list

Archive generated by hypermail 2.1.6.