those ram modules are tough to solder. I think there was some kind of high temp solder used between the ceramic carrier and the SMT chips.. I'd be interested to know how it goes. I recently tossed one out that I also could not debug.
On Mon, Dec 10, 2018 at 8:23 AM <mau...@tiscali.it> wrote: > Hi Jan, yes I knew that, but thank you! > > In this days I payed a bit with my restored M10 and I'm so happy with it :) > Since there are 4 IC in each SRAM module and I have 2 broken modules, I > was hoping to test the single IC to find the individual broken IC and > restore one module mixing the IC of the 2 modules. > A convoluted sentence to say that I'm trying to restore one module out of > 2. > > The idea is also to build 2 more modules with equivalent components.... > > Mauro > > Il 10.12.2018 09:52 VANDEN BOSSCHE JAN ha scritto: > > FYI: the M-10 uses the same modules als the M100. > > Greetings from the TyRannoSaurus > Jan-80 """"" > @ work ( @ @ ) > --------------.ooo--(_)--ooo.--- > > -----Original Message----- > From: M100 [mailto:m100-boun...@lists.bitchin100.com] On Behalf Of Francesco > Messineo > Sent: woensdag 5 december 2018 10:58 > To: m...@bitchin100.com > Subject: Re: [M100] Olivetti M-10's for a new home > > Hi Mauro, > > On Wed, Dec 5, 2018 at 10:52 AM <mau...@tiscali.it> wrote: > > Long story short: SUCCESS!!!!!! My M10 is working fine. Thank you everyone > for the huge help and usefull advise provided in the past and recently. A > BIG THANK YOU to Francesco Messineo I think you neiled the issue and the > chain of event that caused the RAM to fail. Litthe explanation of the > repair process: Removed M3, M4 (decoders), M7, M8, M9 (all my RAM Modules). > Tested M3 and M4 with a TL866 -> good Installed IC machined sockets. > Installed M3 and M4 back in place Installed only one RAM module in M9 > position PC tested -> FAIL Replaced RAM Module PC tested -> FAIL Replaced > RAM Module with the last one available SUCCESS!!!!!! Out of 3, I have 2 > broken RAM modules :) > > I'm glad you solved the problem, I don't think the original modules > can be easily repaired they are made on a kind of ceramic subtrate, > but I might give them a try if you want. > I'm also making replacement modules for the M10 and compatibles since > some years. > You can contact me privately of course. > > I think I don't need another M10 unless I don't want to restore/expand the > RAM size. Do I have other options? Is REX available for the M10? Thank you > everyone Mauro Il 04.12.2018 12:08 mau...@tiscali.it ha scritto: Sounds > possible, thank you!! For the same reason and to get used to the new > desoldering tool I'll first remove and test the 2 decoders M3 and M4 > (40138). Mauro Il 04.12.2018 09:24 Francesco Messineo ha scritto: On Mon, > Dec 3, 2018 at 11:00 PM Mauro Pintus <mau...@tiscali.it> wrote: Checking > some signals with the oscilloscope it looks like it is looping after a fix > time without completing the boot. Francesco Messineo (another user of this > list) wrote me in this days to offer some help and he suspect I damaged the > RAM. Thank you again Francesco. I bought a desoldering iron and I hope in > the next few days I'll find the time to try removing all RAM modules and > fit one at a time in the first socket (hoping one module is still alive). I > actually suggested the RAM could be damaged when he opened SW3 (the RAM > backup power) with SW5 (the main power switch) closed is that some logic > and the RAM have Vb as Vdd rail and almost the rest of the system has Vdd > derived from Vp (via the dual output inverter). Now, if you look at the > schematic, SW3 removes both Vb and Vp, but, on Vb there's only a few bypass > capacitors to ground plus 1 uF electrolytic, so it might discharge quickly, > while on Vp there's at least one 470uF capacitor plus another 470uF on the > output of the inverter on Vdd side (yes, also much more logic powering from > it, but stil...). What might happen in this case is that the Vb got quickly > to 0V with still some inputs of the chips powered from it have something > like +5V applied; in this case, the protection diodes on the input start > conducting and some of them might get shorted or degraded from this > current. It happened a few times on logic that I designed that had a backup > power for CMOS RAM, I had to make sure that all inputs to the RAM were > either following Vbackup or already switched to logic 0 before removing the > backup power. So in this situation I would examine all the logic powered > directly from Vb and that includes the RAMs. Usually a quick test with a > multimeter (with all circuits powered off) from each input pin to Vdd pin > of the chips can show if there's some damaged input protection diode. HTH > Frank IZ8DWF Sent from my iPad On 03/dic/2018, at 19:06, Jan Vanden Bossche > <jan80...@yahoo.com> wrote: Mauro, What do you need to repair your M-10? > Greetings from the TyRannoSaurus Jan-80 ________________________________ > From: Mauro Pintus <mau...@tiscali.it> To: m...@bitchin100.com Sent: > Saturday, 1 December 2018, 16:12 Subject: Re: [M100] Olivetti M-10's for a > new home Thank you Jeff, really appreciated. Now I keep my finger crossed > :) Have a nice day Mauro On Dec 1, 2018, at 3:59 PM, Jeffrey Birt wrote: > Mauro, You have a need for them, so you should have them if the original > person does not speak up. Fixing your machine is a better use. I have no > specific need, just thought it would be neat to have a machine with AZERTY > keyboard. Jeff_Birt From: M100 <m100-boun...@lists.bitchin100.com> On > Behalf Of Mauro Pintus Sent: Saturday, December 1, 2018 7:50 AM To: > m...@bitchin100.com Subject: Re: [M100] Olivetti M-10's for a new home I > was soo exited I didn't see the other answer from Jeffrey, I'm sorry... > Hope we can find an agreement, I'm really interested but I don't want > bother anyone. Mauro On Con OpenStar hai Giga, SMS e i minuti che vuoi da > 4,99€ al mese, per sempre. 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Toute divulgation, copie ou utilisation de ce mail est dans ce > cas interdite. La sécurité et l'exactitude des transmissions de messages > électroniques ne peuvent être garanties. > Denk aan het milieu; druk deze pagina en de bijlagen alleen af als het nodig > is. Dit e-mailbericht (inclusief zijn bijlagen) is vertrouwelijk en is > uitsluitend bestemd voor de geadresseerde. Als dit bericht niet voor u > bestemd is, wordt u verzocht het te wissen en de afzender te informeren. Het > is in dat geval niet toegestaan dit bericht te verspreiden, te kopiëren of te > gebruiken. We kunnen niet garanderen dat de gegevensoverdracht via het > internet veilig en nauwkeurig is. > > > > > Con OpenStar hai Giga, SMS e i minuti che vuoi da 4,99€ al mese, per > sempre. Cambi gratis quando e come vuoi e in più hai 10€ di credito omaggio > e 6 mesi di INFINTY! http://tisca.li/myopen > >
