Re: PinOut of DEC F11 Chips in a Professional 350
> From: Rob Jarratt > The chips where I believe the RESET is oscillating on pin 23 have been > labelled E151 and E152 ... But I am not really sure if I have > identified them and the pin correctly. E151 is the main CPU chip: http://gunkies.org/wiki/F-11_chip_set E152 is the KEF11-A floating point chip, and E150 is the KTF11-A memory management chip. Pin 1 of E150 is definitely in the lower left corner (in the photo); there's an indent on the left-hand side of the chip, for the usual DIP orientation. I'm pretty sure the other two have the same orientation. Noel
Re: PinOut of DEC F11 Chips in a Professional 350
> I'm pretty sure the other two have the same orientation. They do; I looked at the KDF11-A prints in the /23 print set, and then looked at an actual /23. (I should put a hi-res picture of one on the CHWiki page; the one that's there is pretty miserable.) Noel
RE: PinOut of DEC F11 Chips in a Professional 350
Thanks Noel. According to the printset for the KDF11-A pin 23 is the RESET signal, which would make it the 3rd pin from the right at the top right of the CPU. The printset also showed a second chip with its RESET on pin 23 and I have confirmed that E151 and E152 have pin 23 tied together. So I am pretty confident that this is indeed the RESET. I have been tracing the source of the RESET, because as I have said it is oscillating, and it seems to go through a *lot* of logic, and I haven't fully traced the source of the oscillation yet. Regards Rob > -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Noel > Chiappa via cctalk > Sent: 27 October 2018 02:56 > To: cctalk@classiccmp.org > Cc: j...@mercury.lcs.mit.edu > Subject: Re: PinOut of DEC F11 Chips in a Professional 350 > > > From: Rob Jarratt > > > The chips where I believe the RESET is oscillating on pin 23 have been > > labelled E151 and E152 ... But I am not really sure if I have > > identified them and the pin correctly. > > E151 is the main CPU chip: > > http://gunkies.org/wiki/F-11_chip_set > > E152 is the KEF11-A floating point chip, and E150 is the KTF11-A memory > management chip. > > Pin 1 of E150 is definitely in the lower left corner (in the photo); there's an > indent on the left-hand side of the chip, for the usual DIP orientation. > I'm pretty sure the other two have the same orientation. > > Noel
Re: PinOut of DEC F11 Chips in a Professional 350
On Sat, Oct 27, 2018, 04:06 Rob Jarratt via cctalk wrote: > > I have been tracing the source of the RESET, because as I have said it is > oscillating, and it seems to go through a *lot* of logic, and I haven't > fully traced the source of the oscillation yet. > Have you checked the PSU output? My first guess would be bad caps in the power supply. Pat >
RE: PinOut of DEC F11 Chips in a Professional 350
> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Patrick > Finnegan via cctalk > Sent: 27 October 2018 13:48 > To: General Discussion: On-Topic and Off-Topic Posts > > Subject: Re: PinOut of DEC F11 Chips in a Professional 350 > > On Sat, Oct 27, 2018, 04:06 Rob Jarratt via cctalk > wrote: > > > > > I have been tracing the source of the RESET, because as I have said it > > is oscillating, and it seems to go through a *lot* of logic, and I > > haven't fully traced the source of the oscillation yet. > > > > Have you checked the PSU output? My first guess would be bad caps in the > power supply. > I should have said that I have already checked, the ripple is about 100mv peak to peak, which I assume is OK. The green DC OK LED is illuminating too, so I think the PSU is fine. Regards Rob
