Re: Transwarp upgrades

[Ben Zotto <zotto.NO@SPAM.fas.harvard.edu>]

Ed,
Thank you for the excellent information about the oscillators and
chip indications.  It's exactly the level I detail I was looking for.
The FAQ maintaining crew may wish to pop this wisdom in there at some
point when they have a few minutes.

Thanks again, more questions may follow when I figure it out until the
next round!

Cheers
Ben

noone@nowhere.net wrote:
> Ben:
> I usually purchase crystals from digikey.  Keep in mind that minimum
> order of $25 is required to avoid a $5 handling fee.  Usually I spend in
> excess of $25 so it's not an issue.

> As far as opinions upgrading wihtout replacing the CPU chip, the
> following has been learned from trial and error.  Of your CPU chip has a
> '-6', it will probably run at 7-7.5MHz (28-30 crystal).  If you have a
> '-7', it will probably run 8-9MHz (32-36 crystal).  If there is no dash
> number on the chip, they seem stable at 10-11MHz (40-44 crystal).  Keep
> in in mind that anything above 8-8.5MHz may cause your cache ram to
> become the weak link, even if the CPU can handle it.

> I put a socket on my TWGS just so I could use either size crystal, so I
> buy 1/2 size for either a Zip or TW accelerator.  Just make sure you put
> the crystal in correctly or !piff!.  :{  Although >I've< never done
> that... especially with my LAST crystal of appropriate frequency, nope,
> never.  In other words buy a few extra.  (Better to get a couple exta
> crystals than pay the $5 fee.)

> Thankx,
> Ed

> Here is the list from DigiKey's Catalog of compatible 1/2 size crystals.
> (As of 10/2000 anyway.)

> Page 289, Epson Brand, Looks like a DIP with 8 pin package, much better
> selection of frequencies
> 32MHz (8)	SE1111-ND
> 33.333MHz (8.3)	SE1115-ND
> 36MHz (9)	SE1116-ND
> 38MHz (9.5)	SE1117-ND
> 40MHz (10)	SE1118-ND
> 42MHz (10.5)	SE1119-ND
> 44.9MHz (11.2)	SE1120-ND
> 46MHz (11.5)	SE1121-ND
> 48MHz (12)	SE1122-ND
> 50MHz (12.5)	SE1123-ND
> 55MHz (13.75)	SE1124-ND
> 60MHz (15)	SE1125-ND
> 64MHz (16)	SE1126-ND

> Page 295, CTS brand crystals in 1/2 size 'can'
> 32MHz  (8)	CTX174-ND
> 40MHz  (10)	CTX175-ND
> 50MHz  (12.5)	CTX176-ND
> 64MHz (16)	CTX177-ND

> Page 301, ECS brand crystals in 1/2 size 'can'
> 32MHz  (8)	XC254-ND
> 35MHz  (8.75)	XC255-ND
> 40MHz  (10)	X225-ND
> 48MHz (12)	XC256-ND
> 50MHz (12.5)	X226-ND
> 64MHz (16)	XC257-ND

> Ben Zotto wrote:
>> So I'd like to do something with it, and it seems a straight speed
>> upgrade is best.  (Opinions on this welcome).  I figure without
>> getting a new chip from WDC I can probably try a 32Mhz oscillator
>> or even a 36Mhz one?  Can anyone offer an opinion on this, or
>> tell me where a good place to find such oscillators is?