I’ve come across an original copy of rare document, the KLH Research and Development Corporation SOLID STATE COMPONENTS CROSS REFERENCE GUIDE (6 Februrary 1970).
This shows recommended substitute transistors for many of the components used in KLH equipment. You can use this information to substitute a different transistor on most models if needed, including many transistors which were identified only with house part numbers.
I’ve transcribed the guide here in full because of the quality of the original, this will be more readable, and it will also be more easily searchable this way for anyone looking for specific substitutes with a search engine, LLM, or AI agent search.
KLH Research and Development Corporation
SOLID STATE COMOPNENTS CROSS REFERENCE GUIDE
(6 February 1970)
Code used with some transistor types:
+ Different Base Configuration
* Poor Reliability History
| Item (Original Transistor Part Number) | Substitute (Replacement Transistor Part Number) |
| 2N408 | 2N2429 2N2613 GC1081 SA853 |
| 2N990 (P/N 0131-00498) | 2N2671 2N3324 AF125 SM2491 TI403 |
| 2N1304 | |
| 2N2147 (P/N 0131-000336) | |
| 2N2148 | 35547 |
| 2N2429 (P/N 0131-002656) | 2N2613 35045 GC1081 SA853 |
| 2N2431 (P/N 0131-001050) | |
| 2N2613 (P/N 0131-000101) | |
| 2N2614 (P/N 0131-000563) | 36789 |
| 2N2654 | 2N3588 TI401 |
| 2N2671 (P/N 0131-001435) | 2N990 AF125 |
| 2N2904 | 2N4031 37793 S1970 |
| 2N2924 | 2N3391A 2N3392 2N3707 BC168A KLH704 MPS3392 + MPS3707 + |
| 2N3053 | S1971 SE8002 36145 38107 |
| 2N3055 | 38272 SJ3481 |
| 2N3286 (P/N 0131-001182) | AF106 SM2492 |
| 2N3324 (P/N 0131-001314) | 2N990 2N3588 SM2491 TI403 [Ed. Note: Fixed typo in original here.] TIM11 |
| 2N3391A (P/N 0131-001422) | 2N3707 MPS3707 + SE4010 + TI415 |
| 2N3392 (P/N 0131-000704) | 2N3391A 2N3787 BC168A KLH704 ME4002 MPS3392+ MPS3707+ SPS4347+ TI417 |
| 2N3588 (P/N 0131-001433) | 2N990 2N3324 SM2491 TI401 TIM11 |
| 2N3645 * | SK7840 SPS1523 |
| 2N3702 (P/N 0131-001439) | TIS03 |
| 2N3707 (P/N 0131-001417) | 2N3391A MPS3707 + SE4010 + |
| 2N3710 (P/N 0131-001421) | 2N3391A 2N3392 2N3393 2N3707 BC168A KLH704 ME4002 MPS3392 + MPS3707 + SE4010 + SPS4347 + TI417 |
| 2N4031 | 2N2904 37793 S1970 |
| 2N4122 (P/N 0131-001438) | MPS6518 SPS4348 + |
| 2N4241 | 35044 SPS2234 + TI3027 + |
| 2N4249 (P/N 0131-001420) | SPS4348 + |
| 35044 (P/N 0131-000562) | 2N4241 SPS2234 + TI3027 + |
| 35045 (P/N 0131-000101) | 2N2429 2N2613 GC1081 SA853 |
| 35547 (P/N 0131-000337) | 2N2148 |
| 36145 (P/N 0131-000561) | 2N3053 38107 S1971 SE8002 |
| 36789 (P/N 0131-001426) | 2N2614 |
| 37267 (P/N 0131-001007) | B270002 SES553 SJ3464 38272 |
| 37793 (P/N 0131-001428) | 2N2904 2N4031 S1970 |
| 38107 (P/N 0131-001429) | 2N3053 36145 S1871 SE8002 |
| 38629 (P/N 0131-001598) | SPS4370 + |
| 38270 (P/N 0131-001591) | |
| 38271 (P/N 0131-001592) | |
| 38272 (P/N 0131-002068) | 2N3055 SJ3481 |
| AF106 (P/N 0131-001436) | 2N3286 SM2492 |
| AF124 | 2N990 |
| AF125 (P/N 0131-001697) | 2N990 2N2671 |
| B270002 (P/N 0131-001431) | 37267 SES553 SJ3464 38272 |
| BC168A | 2N3391A 2N3392 2N3707 KLH704 ME4002 MPS3392 + SE4010 + SPS4347 + TI415 TI417 |
| GC1081 (P/N 0131-000100) | 2N2429 2N2613 35045 SA853 |
| GC1082 (P/N 0131-000102) | 2N2429 2N2613 35045 GC1081 SA853 |
| GC1082A (P/N 0131-000560) | |
| GC1566 | TI400 AF106 |
| GC1570 | 2N990 GC1573 SM2491 TIM11 |
| GC1573 (P/N 0131-001332) | 2N3286 AF106 SM2492 TIM11 |
| KLH704 (P/N 0131-000704) | 2N3391A 2N3392 2N3707 BC168A ME4002 MPS3392 + MPS3707 + SI704 SPS4347 + TI417 |
| ME4002 | 2N3391A 2N3392 2N3707 BC168A MPS3392 + MPS3707 + SPS4347 + TI417 |
| MPS3392 (P/N 0131-001418) | 2N3381A + 2N3392 + 2N3707 + BC168A + KLH704 + ME4002 + MPS3707 SE4010 + SPS4347 TI417 + |
| MPS3707 (P/N 0131-001424) | 2N3391A + 2N3707 + SE4010 + TI415 + |
| MPS6512 | MPS6513 MPS6514 |
| MPS6513 (P/N 0131-001864) | MPS6512 MPS6514 |
| MPS6514 | MPS6512 MPS6513 |
| MPS6518 | SPS4348 |
| MPS6530 | SPS4373 |
| MPS6433 | SPS4347 |
| MPS6534 | SK7840 SPS1523 |
| S1970 (P/N 0131-001427) | 2N2904 2N4031 37793 |
| S1971 (P/N 0131-001430) | 2N3053 36145 38107 SE8002 |
| SA853 (P/N 0131-001419) | 2N2429 2N2614 35045 GC1081 |
| SE4010 (P/N 0131-001423) | 2N3391A 36145 38107 S1971 |
| SE8002 | 2N3053 36145 38107 S1971 |
| SES553 | 38272 37267 B270002 SJ3464 |
| SF7718 (P/N 0131-001263) | SS3604 |
| SF7946 (P/N 0131-001264) | SS3605 |
| SG4825 * | 2N2904 2N4031 37793 S1970 |
| SI704 | 2N3391A 2N3392 2N3707 BC168A KLH704 ME4002 MPS3392 + MPS3707 + SE4010 + SPS4347 + TI417 |
| SJ3464 (P/N 0131-001548) | 37267 B270002 SES553 38272 |
| SJ3481 (P/N 0131-001597) | 2N3055 38272 |
| SJE267 (P/N 0131-002049) | |
| SJE268 (P/N 0131-002049) | |
| SK7840 (P/N 0131-001328) | MPS6534 SPS1523 |
| SM2491 (P/N 0131-003029) | 2N990 2N3324 2N3588 TI403 |
| SM2492 | 2N3286 2N3588 AF106 TI403 |
| SPS1523 (P/N 0131-001329) | SK7840 MPS6534 |
| SPS2234 (P/N 0131-001425) | 2N4241 + 35044 + TI3027 |
| SPS4347 (P/N 0131-001464) | 2N3392 + BC168A + KLH704 + MPS3392 |
| SPS4348 | 2N4249 |
| SPS4370 (P/N 0131-001594) | 38269 |
| SPS4371 (P/N 0131-002045) | |
| SPS4372 (P/N 0131-002046) | |
| SPS4373 (P/N 0131-002047) | |
| SPS4374 (P/N 0131-002048) | MPS6533 |
| SS1907 * | 38270 |
| SS1908 * | 38271 |
| SS3604 (P/N 0131-001437) | SF7718 |
| SS3605 (P/N 0131-002015) | SF7946 |
| TI400 (P/N 0131-000419) | AF106 GC1566 |
| TI401 (P/N 0131-000418) | 2N2654 2N3588 |
| TI403 (P/N 0131-000802) | 2N3588 TIM11 |
| TI415 | 2N3391A 2N3707 MPS3707 + SE4010 + |
| TI417 (P/N 0131-000473) | 2N3391A 2N3392 2N3707 BC168A ME4002 MPS3392 + MPS3707 + SPS4347 + |
| TI3027 (P/N 0131-000192) | 2N4241 35044 SPS2234 + |
| TIM10 (P/N 0131-001434) | 2N3286 AF106 SM2492 |
| TIM11 | 2N3286 2N3324 AF106 GC1573 SM2492 |
| TIS03 (P/N 0131-000335) | 2N3702 |
| TIXM01 * | 2N3286 TIM02 TIM03 |
| TIXM02 (P/N 0131-000862) | 2N3286 TIM03 |
| TIXM03 (P/N 0131-000863) | 2N3286 TIM02 |
| TIXM202 (P/N 0131-000859) |
This is the full transcribed text of the original document, hopefully it helps you with replacing transistors in a KLH device from the late ’60s like a Model 20 or Model 24/25.
