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MODERN REPLACEMENTS FOR IBM 091 TRANSISTOR AS USED IN THE 1620 DATA PROCESSING SYSTEME-mails from David Wise, David_Wise at Phoenix. dot com
- January 16, 2022
- January 18, 2022
January 16, 2022
MODERN REPLACEMENTS FOR IBM 091 TRANSISTOR AS USED IN THE 1620 DATA PROCESSING SYSTEM SUMMARY AT THE END Updated August 2021 for parts availability Used in the Type FM Current Driver card. Also applies to the DKA card in the 1401, which is effectively identical. Also applies to the DFV/DFW/DFY cards in the 1410. The 1410 needs one of the heat-sinked approaches, and the DFV card requires 100V. I suggest 2SC5706 for all. I have seen a photograph of an FM card with a Type 087 transistor; therefore, my research below probably applies to 087 as well as 091. March 2015 May-August 2016 2019 May 2017 ----------------- My 1620 core array has failed! Two open-circuit Y half-select lines, 0xx52 and 1xx98. I will try to repair them sometime. Meanwhile, I'm using the solid-state ram board. It's easy to confirm on the scope, just probe across the suspected matrix switch output winding, with the 1620 set to hammer on the bad address. Good = 5V pulse, bad = 25V pulse. Ghod knows what it's doing at the transistor. TODO: 1. Disable matrix switches. Ground pin C of at least one MSA and one MSD current driver. 2. Repair core. I don't want all my transistor work to become irrelevant. There's no sign of corrosion; I think it just broke from 60 years of thermal cycling. Probably right at the terminal. Even so, disconnecting the stack from 200+ wires will be tedious. Maybe I can get by without disconnecting. This will be a good winter project. 3. Create as-built ram board schematic. -------------------------- I thought these would also work for 086 (FL/ARW Decode Switch) and 071 (WJ MARS/Inhibit Driver), but most parts suited for FM are too slow for FL, and those suited for FL are too slow for WJ. See Decode_and_Inhibit_Candidates.txt . There is no one sweet spot for all, it mostly takes a different type for each job. Note: Silicon in FL requires a 9V zener in the emitter lead to prevent B-E breakdown. The zener must be an ordinary diode drop in the forward direction. It must also "reverse recover" faster than the B-E diode. All three cards switch 300mA, but 086 switches "cold", and 071 has a lower Vce (12V excluding transients). Therefore, 086 and 071 max ratings are not as stringent. But they are saturated, and need to be fast even so. Especially the 071, because Ibb2 is low. That means they have to be more agile and therefore smaller. CAVEAT! Some of these substitutions have not been tested yet. The Current Driver card has more heat sink than Decode and Inhibit. Due to 091's unique heat spreader design, the IBM heat sink is incompatible with all substitutes. But power dissipation is less than one watt, and 091 needs the big sink only because it's Germanium. Silicon parts don't need much, especially with forced-air cooling. I suggest some models below anyway. Beta = 30 is the theoretical minimum. I insist on 40, at 1V/300mA. The part I am currently using is the TO-220 D44C8, on a small heat sink modified for low profile. The FM card was designed to get 1V when beta is 100. The limiting case is 1.6V and beta 30. With Si, this shifts to 1.4V and 1.8V. (1.1V when beta is infinite.) If you decrease the 91-ohm resistor to 68 (e.g. by paralleling 270), Vce shifts back to the design values of 1V and 1.6V . The bad 091 measures 35pF at 9V. D44C8 Cob is 100pF max at 10V; measures 45pF at 9V. Anything less should be okay. D44H11 Cob measures 65pF at 9V, so more is going on than just Cob. D44C8 fT is 40MHz max at 20mA/4V. We want the spec at 2V/300mA. NOTE: Since the circuit reverse-biases the B-E junction, BVceo is not relevant. The voltage specs below are BVcbo. I assume no punch-through. (If BVces == BVcbo, that's guaranteed.) Distinguishing Avalanche Breakdown and Punch-through Avalanche won't oscillate or pull to ground without shunt capacitance. Punch-through falls right to ground, super fast (1ns), and oscillates without capacitance. My 2N1304 avalanches (around 75V), my BC337 punches through (around 150V). I read a patent for adding controlled punch-through to a process, that said it gave better reliability than avalanche. Motorola? Can't remember. Anyway, maybe all modern parts are built to punch through. I used a HV power supply and 10K 10W to collector, base+emitter grounded, and 15K 1W from collector to scope with 50-ohm termination. Transistor gets hot, run for one minute unless cooled. WARNING - If you use a sampler, include at least 20dB of 50-ohm attenuation ahead of the series resistor, to prevent the transient coupled through the resistor's parasitic capacitance from blowing the sampling diodes. Look at this again at DC. Punch-through is happening when emitter and collector rise and fall together, one volt change at C causes one volt change at E. Compare to Beale et. al. who say that punch-through is when reverse-biasing the base doesn't stop the oscillation. JUST LEAVE IN THE AIR Absolute minimum tooling, labor, and materials. These parts have beta to spare and will run less than 1.4V / 0.42W / 120C Tj. And that's in still air at 35C 95F i.e. fan failure. TO-92 SC-71 E-Line BC337 50V 0.8A SOA .2A@45V .3A@40V KSD1616A 120V 1A SOA .15A@60V .3A@40V Works in FM card MPS650 60V 2A MPS651 80V 2A SOA .4A@60V Works in FM card STSA1805 150V 5A Slightly slower than D44C8, should be fine ZTX449 50V 1A ZTX650 60V 2A ZTX651 80V 2A SOA 1A@60V ZTX692B 70V 1A SOA .7A@70V ZTX851 150V 5A SOA 1A@60V ZTX1053A 150V 3A SOA .6A@75V ZXTN2010A 150V 4.5A SOA 1A@60V NEAR ORIGINAL LOOK Pot the above in the original heat sink. It's a lot of work, and I don't know how much heat it can dissipate. PROCEDURE 1 Make a 0.100" thick heat spreader disk that's a smooth tight fit in the heat sink. 3/8" rod; grind down to 0.325". Cut a radial slot for the transistor leads. Cover the bottom with tape, slit to match the slot. Wrap the transistor leads for 0.125" with a strip of tape. Wrap a tube of tape around the disk. Stick the transistor in the slot. Fill the annular space around the transistor with thermal epoxy. After it sets, peel off the tube of tape. Form the transistor leads to hit the TO-5 pads. Coat the heat sink cavity lightly with thermal grease. Observing lead orientation, insert the potted transistor into the heat sink. PROCEDURE 2 (more steps but no machining) Find a straw slightly larger than the hole. Snip off 3/16". Coat the hole with thermal grease, then wipe off gently leaving a thin film. Cover the hole on the bottom with Scotch Magic Tape et. al. Install the heat sink. With a needle or pin, poke small holes for the transistor leads. Form the transistor leads to match the old TO-5 EBC pin circle. Slip the transistor into place through the holes but do not solder. Seal the holes with dabs of white glue on the end of a toothpick. Coat the inside of the straw piece with thermal grease. Put a bead of white glue on the bottom edge of the straw piece. Position the straw piece on the heat sink and secure with tape. Wait for the glue to dry. Remove the tape securing the straw piece. Fill the cavity with epoxy. Wait for the epoxy to set. Solder the transistor leads. SOLDER TO COPPER-CLAD PCB (through hole leads) TO-251 Drill mounting holes and one big hole, attach wires and cover with tubing, solder wires into SMS card. 2SC4135 100V 2A 15pF typ 2SC5706 100V 5A SOA 1A@100V 15pF typ SOLDER TO COPPER-CLAD PCB (surface mount leads) (no testing done) TO-252 2SC5706 2SD1816 120V 4A SOA .5A@50V 40pF typ 2SD2318 NRND MJD44H11 80V 8A 45pF typ, not as slow as D44H11 NSS1C301ET4G STD1802 fT at 50mA SOT-223 2STN1360 DNLS350E FZT651 NSS1C201MZ4 (or NSV) NZT560 NZT651 (Fairchild tech support says fT is 50MHz min at 500mA) NZT902 NZT6717 PBSS4350Z PBSS8110Z PZT651 STN851A METAL CAN TO-39 Minimal tools and labor, but parts are expensive. The parts below are untested. If they are too fast, you can add a slowdown cap on the component side, provided the holes are big enough for two leads. Mine are. No heat sink; if TO-92 doesn't need it, we don't either. NTE16005 claimed sub but might be slow like 2N3421 2N5320 100V 2A CEN $3.09 Beta reads 65 at 300mA/1V, maintained down to 0.3V 2N5321 75V 2N3507 MOT see Motorola-SeminarsandApplicationBooksSmall_Signal_Transistor_Data-DL.pdf $$$ 2N3735 MOT Motorola-SeminarsandApplicationBooksSmall_Signal_Transistor_Data-DL $$$ 2N4895 $$$ BOLT TO COPPER-CLAD PCB OR LOW-PROFILE HEAT SINK Wakefield 242-125ABE-22 or 274-3AB, Aavid 592502B03400G or 577002B00000G, CUI HSS-B20-0635H, cut off mounting tabs, and elevate with nut plus washer to avoid scratching the SMS card. 0.125" brings total height to 0.346", which is less than Type 028 (tall TO-5) height of 0.385". 60K rise at 2W natural convection. TO-126/TO-225/SOT32 BD137 60V BD139 80V 1.5A SOA 1A@80V MJE180 60V MJE181 80V MJE182 100V 3A SOA .2A@80V .3A@60V .8A@40V Works in FM card TO-202 CEN-U05 60V 2A CEN-U06 80V CEN-U07 100V TO-220 D44C8 60V 4A 100pF max In use. Speed equals 091. NOTE: EOL! DISQUALIFIED QUASI-SATURATION BC639 1A (observed on curve tracer) KSC1008 0.7A (observed on curve tracer) MJE243 4A (observed on curve tracer) PN3569 0.5A 2SC3902 1.5A 2SC4027 1.5A 2SC4134 2SC4135 2SC4488 120V 1A 2SC4614 1.5A 2SC5171 2A 2SC6097 60V 3A 2SC6098 2SC6099 2SD1733 2SD1815 120V 3A INSUFFICIENT BETA (Some of these parts may work in FL or WJ; FM provides less bias.) 2N1613 2N1711 2N2102 2N2219A 2N3053 2N4401 2N5681/2 2SC3332 BD241A/B/C KSC2331 Works in 1620 - barely ZTX450 ZTX451 ZTX452 ZTX453 ZTX454 ZTX455 SLOW (fT or Cob) 2N3420 150pF 2N3421 125V 2A 40@1A/2V 40MHz 150pF CEN $3.33 19V on test jig 2 2SC6082 2SC6144 2STN1550 fT not given BC141 Tested slow BCP55/6 NXP: fT at 50mA; ON: steep drop after 100mA BD237 BD239 BD787 4A. Jig 2: Ts=200ns Tf=200ns 20V D44H11 Works in 1620! But slow. KSP05/6 Steep drop MPSA05/6 Steep drop KSC2316 Tested slow KSC2334 fT/Cob not given KSC2383 Tested slow KSC2690 Tested slow KSD526 KSD1588 KSD1691 fT/Cob not given TIP29A/C 3MHz INSUFFICIENT POWER DISSIPATION 2N1304 150mW INSUFFICIENT BVcbo Since FM reverse-biases by one diode drop, the criterion is somewhere between BVces and BVcbo. The emitter is at -12V, so a 30V spike is 42V. I think 60V is fine, maybe 50V. MPSW01 40V DISCONTINUED 2N3725 EOL 80V 1.2A CEN $4.24 EOL 2021-03 2N4896 2N6715 2N6716 2A Use MPS651 2N6717 80V 1A Use MPS651. 1800 in stock, $1.62 . 2N6718 2A Use MPS651 2SC2655 50V 2A 2SC4487 60V 3A 2SC6017 EOL 100V 10A SOA 3A@50V 60pF typ, might be slow 2SC6043 80V 2A 2SD1207 60V 2A 2SD1683 2SD1801 EOL 60V 2A 12pF typ 2SD1802 EOL 60V 3A 25pF typ 2SD1803 EOL 60V 5A SOA 2A@50V 40pF typ 2SD1816 OBSOLETE 120V 4A SOA .5A@50V 40pF typ 2SD1835 60V 2A D44C8 ON discontinued in 2018, NTE still has D44C11 in stock but do not use NTE377 cross, it's D44H11 MPSW05 MPSW06 TN2219A TN6715A Since the Current Driver card is unsaturated, the saturated switching speed is irrelevant. But fT (at 2V/300mA) and Cob are important. And there must be no quasi-saturation. >>>> 086 (FL) and 071 (WJ) are used in saturated mode! Claimed to be ok by Bob Hunter replacement list: 071 2N377 2N647 2N1302 086 2N214 2N557 2N1302 2N1304 091 2N214 2N228 2N557 2N1302 I have no direct experience with the following IBM parts but believe the suggested replacement is not adequate. 092 2N228 but IBM-StandardModularSystem-Neff7.pdf says 1250mA (pg 141) 093 2N228 but IBM-StandardModularSystem-Neff7.pdf says 400mA (pg 220) From Towers International Transistor Selector: 2N214 TO-22 40V 100mA 44min@35mA 300kHz 2N228 TO-22 40V 100mA 80tp@1mA 200kHz 2N377 TO-5 25V 200mA 20-60@30mA 3MHz (2N377A is 40V) 2N557 TO-5 20V 200mA 20mn@1mA fT not specified 2N647 TO-1 25V 50mA 70tp@50mA fT not specified 2N1302 TO-5 25V 300mA 20-80@10mA 1MHz. 2N1304 same except 40-200 and 4MHz From New Jersey Semi datasheet 2N1304 300mA absolute maximum. Beta@200mA is 15 minimum 110 typical. 071, 086, 091 require 300mA so 2N214 2N228 2N557 2N647 disqualified 086 sees 30V transients so 2N130x disqualified 091 sees 42V transients so 2N130x disqualified As you can see, the Hunter list is wrong except possibly 2N130x for 071. No, it's wrong there too: in datasheets from Central Semi, New Jersey Semi, and RCA, beta is 15 or 20 at 200mA so it will be less at 300. Unless you select for BV, hFE, and speed. My West German-made 2N1304's are fine for FL. (But too slow for FM and WJ.) TO-5 (except as noted) NPN Germanium with Vcb >= 30V and Ic >= 300mA 2N356A 30V 500mA 20-50@100mA 1MHz 2N357A 30V 500mA 25-75@200mA 2MHz 2N358A 30V 500mA 25-75@300mA 4MHz 2N440A 30V 300mA 40mn@50mA 5MHz 2N576A 40V 400mA 20-60@400mA 3MHz >>>>MAYBE 2N625 40V 500mA 20mn@500mA - TO-8 2N821 30V 400mA 40mn@50mA - OBS PKG 2N822 30V 400mA 40mn@50mA - OBS PKG 2N1170 40V 400mA 20mn@200mA 3MHz None of these has enough BV to replace 091, but 2N358A or 2N576A can probably replace 071 if fast enough. Silicon from Towers: (All disqualified.) 2N697 60V 500mA 40-120@150mA 50MHz Insufficient beta at 300mA 2N1613 75V 600mA 40-120@150mA 80MHz 2N1711 75V 600mA 100mn@150mA 70MHz 2N2102 120V 1A 40-120@150mA 60MHz (Typo, Towers says 10mA) 2N2219A 75V 800mA 100mn@150mA 300MHz 2N3053 100V 700mA 50mn@150mA 100MHz Germanium from D.A.T.A. 1962 Line Part 885 2N1170 1586 2N1473 40V 400mA 50@400/0.6 15pF 8Mc(f alpha b) 2293 2N1965 Error - this is silicon, and not TO-5 CLAMPING ANALYSIS The FM card puts 12V through 510 ohms, then clamp diode, then 91 ohms, then 8mA sink to -36V. If you assume .3V diode drops and beta=100, it balances at Ib = 300/100 = 3mA, so 11mA through 91 ohms. .3+(.011*91) = 1.3V . Assume 0.7V drop in the driver. (12-1.3-.7) = 10V drop across the 510 for 19.6mA, which implies 8.6mA through the clamp diode, whose .3V drop means Vc = 1V . Repeat for Silicon. .7+(.011*91) = 1.7V . Assume 0.7V drop in the driver. (12-1.7-.7) = 9.6V drop across the 510 for 18.8ma, which implies 7.8mA through the clamp diode, whose .3V drop means Vc = 1.4V . Clamping failure occurs when the diode conducts negligible current. I91 = (12-.7-.3)/(510+91) = 11/600 = 18.3mA. Ib = 18.3-8 = 10.3mA . .3V+(.0183*91) = 2V, which .2V diode drop reduces to Vc = 1.8V . At clamping failure, beta is 300/10.3 ~= 30. Repeat for Silicon. I91 = (12-.7-.7)/510+91) = 10.6/600 = 17.7mA or Ib = 9.7mA. .7V+(.0177*91) = 2.3V, which .2V diode drop reduces to Vc = 2.1V. Beta is 300/9.7 ~= 30. TEST JIG 1 2N4401 driver. Emitter at -3V. Base drive is +/-5V through 1K. 180 ohm collector load to +5V. One Si diode to DUT base then 470 to -3V. DUT collector has Si diode to driver collector, and 51 ohm 2W carbon comp load to +17V. 10uS active-low pulse (DUT usually off) and 20kHz rep rate to avoid overheating Rload. Ib(supply) = (5V-1.4)/180 ohms = 20mA. Ibr = 3.7V/470 ohms = 7.9mA ~= 8mA. If beta = 100, Ib = 3mA, Id1 = 11mA, Id2 = 9mA, and Vc = .7V. At failure, Ib = 20-8 = 12mA, Id1 = 20mA, Id2 = 0, Vc = 1.4-.5 = .9V ~= 1V. Looks like this is off a bit, because everything reads .8-1.1V with 1.1V still showing clamp action. READINGS Note: The 091 data below is an old measurement on an FM card, so it is not exactly commensurable. Tf is a guess based on voltage spike height, which equals D44C8. Ts is fudged to follow the difference between other Ts readings here and their analogues in the old FM test run. Any part with short Tf can be slowed down with a Miller cap. For example, 36pF on BD139 gives 70ns. Sorted by Tf Type Ts Tf Vc 091 130 90 1.0 086 80 230 .7 BD139 30 20 1.0 MPSW3725 45 30 1.0 MPS651 45 40 .9 TN2219A 75 40 1.1 TN6715A 50 45 .9 2N2219A 75 45 1.1 PN2222A 90 50 1.0 Slow start KSC2331 120 50 .9 2N4401 100 55 1.0 Slow start KSD1616A 40 60 .9 D44C8 70 90 .9 ------------------------ STSA1805 60 120 .8 MJD44H11 80 140 .9 TN3019A 250 180 1.0 Slow start BC141-16 200 250 1.1 SLOW start D44H11-ST 120 300 .8 Works in 1620 but don't know how well 2N1304 80 320 1.1 REAL FM CARD With Milwaukee resistor pullup instead of current source. The numbers come from scoped voltage rise at the load resistor. The speedup cap saturates the transistor for about 400ns. Type Ts Tf 091-1 100 120 Cards from K2 and H3 091-2 100 200 Card from K28 2N5320 0 100 2SD1803 0 140 STSA1805 0 160 MJD44H11 0 160 D44C8-GE 0 180 Card from K27 D44H11 0 400 2N3421 0 450 TEST JIG 2 This is closer to real life. 2N4401 driver. (15 ohms in collector, does not affect FL or WJ mode.) Emitter at -3V. Base drive is +3V/-7V through 270 ohms. 160 ohm collector load. Two Si diodes to DUT base and 470 to -3V, to check temperature, or one diode to check clamping. DUT collector has Si clamp diode to driver collector, and 56 ohm 20W WW, Milwaukee type 43X302 load resistor to +17V. +4V (one diode) or +4.7V (two diodes), -3V, +12mA max, -8mA. 50kHz rep rate, short active-high pulse (DUT usually on to maximize saturation), adjust Vcc for 300mA average current, adjust pulse width to get one peak plus a bit. This is slower than real life: Tf for D44C8 is 120ns and Vspike is only 30V across the transistor whereas real Vspike is 30V across the load and 42V across the transistor. Maybe the resistor's Q is lower than the 1620. To avoid extra stress on the Decode Switches, on fast parts we add a Miller capacitor to reduce the spike to D44C8 size. (Which in turn matches IBM 091.) I use this jig to pick the cap. MPSW3725 47pF 2N2219A 33pF (45C rise with heat sink) BC337 33pF MPS651 33pF MJE182 22pF KSC2331 22pF KSD1616A 22pF (50C rise in still air) 2N5320 22pF 2SC5706 22pF 2SD1801 22pF 2SD1815 15pF BD139 15pF 2SD1802 10pF 2SD1803 0pF 2SD1816 0pF D44C8 0pF (30V peak, reference) STSA1805 0pF (26V peak) MJD44H11 0pF (24V peak) D44H11-ST 0pF (21V peak) 2N3421 0pF (19V peak) BC639, BD139, and MJE243 I bought off eBay are counterfeit. (The fake BC639 would work, but I don't use fake parts.) Notes above are for real parts. My 2N2219A works, but old typical curves from Motorola Small-Signal-1984 are unacceptable. Not recommended. IN-SYSTEM MEASUREMENTS Rediscover real FM performance, turn on and turn off. Maybe the turnoff spike is a bug not a feature. Maybe we really want to minimize it, not match 091. Does it affect the in-circuit current ramp if we suppress it with a Miller cap? Scope output current in 1620, triggered on falling edge of FM control input. How big/slow before turnon is too slow? Before the speedup cap is too small? (A: Speedup cap overwhelms any sane Miller cap.) Try with KSD1616A no cap, KSD1616A with 450ns worth of cap, 2N3421, and bad 091. RESULTS: BC337 with 47pF is non-monotonic BC337 with 82pF is monotonic, current turnon in 1620 10%-90% is 500ns In order of ease of installation: (1) TO-92 STSA1805; (2) TO-92 BC337, KSD1616A, or MPS651, plus cap; (3) TO-251 MJD44H11, soldered to copper; (4) TO-251 2SC5706, 2SC4135, soldered to copper, plus cap; (5) TO-220 D44C8 bolted to aluminum or copper; (6) TO-126 MJE182 or BD139 bolted to aluminum or copper, plus cap; (7) TO-252 2SD1816 etc soldered to PCB (8) TO-92 Potted in original heat sink. During testing, I observed that the cap caused VHF oscillation in the 1620. (It didn't show up on the bench.) This goes away when you eliminate the jumper lead inductance. Fast parts operated fast cause Iout to rise, fall, and rise again, which is bad. I think it's instructive to the next maintainer to use a fast part with cap instead of a slow one that happens to be right. It will make them think. I think it's not worth it to make a custom circuit board for surface-mount parts. Fun fact: Nobody can do WJ and FL and FM. BC337 and MPS651 can do FL and FM. Except for the Baker Clamp Boys, nobody can do WJ and FL.
January 18, 2022
Thanks, Robert. I havenít read Kenís paper but I certainly will.
2N4401 is one of my recommendations for the 086 in the 1401 AQU Decode Switch card. It can also replace 071 in the MARS/Inhibit cards. Other AQU parts are BC337, KSC1008, and MPS651. I use the MPS651 (with zener) in my 1620 FL cards that lost their 086. Itís a fine part, still cheap and abundant, and it can also be used for the non-saturating Current Driver cards. KSC1008 is fine replacing the Decode Switch 086, but not usable for Current Driver 091 because it exhibits quasi-saturation which renders the Baker clamp ineffective. For my one failed FM card (091), I used a D44C8 for years. They are discontinued now, but a number of still-living parts look fine on datasheet and jig, and a few of those have been confirmed to work perfectly in the 1620, with waveforms almost indistinguishable from 091. (That testing came to a halt when one then another Select line went open-circuit. If they broke at the terminal, it may be possible to repair them. SomedayÖ)
The Current Driver 091 was heavily heat-sinked, but even though Silicon parts run hotter unless you tweak the Baker clamp, they can handle it easily and will probably even survive a fan failure. Even the TO-92ís.