Finding Manuals and Schematics (Let me know of any I should add)

These sites have some overlap, listed under primary category.  Sites with multiple categories (like Heathkit) and manual purchase sites are listed at the end.  Many of these are sub-pages of excellent sites with much more information - plan on checking out the rest!

Find your Model or Chassis Number

Pictures by manufacturer: https://radioatticarchives.com/
More pictures: https://antiqueradios.com/gallery/main.php
Car radios: https://www.retroradioshop.com/pages/identifying-car-radios-by-image-buick-full-size
Catalogs - Allied, Heathkit, Lafayette, Radio Shack, etc: https://worldradiohistory.com/Electronics_Catalogs.htm
You can also do a photo search at https://www.radiomuseum.org/
Radio Finder DB will list models if you enter tube list: https://www.grillecloth.com/
Radio Shack Catalogs (1939-2010): https://www.radioshackcatalogs.com/
Allied Catalogs (1929-1982): https://www.alliedcatalogs.com/
EIA (RMA before 1957) codes may ID parts and date: EIA 1962 Code List     All EIA Code Lists 1946-2001
Silvertone 1931-37 models : http://coloradoradiocollectors.com/CRC/index.php/knowledge/resourses/catalogs/sears-silvertone-radios-1931-1937-part-i
Once you have a model #, download and run this program - it's an index to Beitman's, Rider's, and Sams (alternate)

Antique Radios

Rider's (by manuf. / model) at http://www.nostalgiaair.org/Resources/
Rider's (by volume) at https://worldradiohistory.com/Rider-Manual.htm
Beitman's at https://worldradiohistory.com/Beitman-Manual.htm
Canadian: https://radio.codegods.ca/
Radiomuseum (close to a million schematics!): https://www.radiomuseum.org/
European Radios: https://www.radiotechniek.nl/
A few by Brian McAllister: http://oldtech.net/
5000+ at Archive.org: https://archive.org/details/Radio_Schematics
DOCTSF (France): https://archives.doctsf.com/documents/index.php?num_serie=56
Kevin Chant (mostly Australian): https://www.kevinchant.com/
Luca Rossi (Italy): https://digilander.libero.it/chopin.i/radio/index.html
TV - Pre WWII: https://www.earlytelevision.org/tv_schematic_diagrams_prewar.html
TV - Postwar: https://www.earlytelevision.org/postwar_tv_schematic_diagrams.html
TV - Early Color: https://www.earlytelevision.org/tv_schematic_diagrams_color.html

Atwater Kent: http://www.atwaterkent.info/TechData/akSvcDataIndex.html
Crosley: http://www.crosleyradios.com/manuals_and_instructions.html
Crosley, Philco, others: http://silverslingshot.com/
Philco: https://philcoradio.com/library/index.php/service-info/
Philips: http://mario.datastress.com/index.shtml
RCA: https://worldradiohistory.com/RCA-Victor-Service.htm
Stromberg Carlson: http://www.audiophool.com/MadeInRoch.html

Audio

A few from the '50s: http://www.audiophool.com/hifistuff.html
Ampslab: https://www.ampslab.com/vintage1.htm
Analog Rules! (pro audio): https://www.analogrules.com/manual_list.html
Audio-circuit.dk: https://audio-circuit.dk/
AudioKarma Database: http://akdatabase.com/AKview/
Audio Service Manuals: https://www.audioservicemanuals.com/
Film Sound: http://www.film-tech.com/warehouse/index.php?category=2
Gyraf's Obscure Schematics: https://gyraf.dk/schematics/schematics.html
HiFi Engine (must register): https://www.hifiengine.com/manual-library.shtml
HiFi Manuals: http://www.hifi-manuals.com/
OneElectron: https://www.one-electron.com/Archives/Techs_FC/filing_cab.html
Pacific TV- US and Canadian: http://www.pacifictv.ca/wanted.htm
The Tube Store, a few: https://www.thetubestore.com/hifi-amp-schematics
Technical Audio: http://www.technicalaudio.com/pdf/
Triode Electronics: http://www.triodeel.com/schindex.htm
Vintage Hi Fi: https://www.vintageshifi.com/m800.php
Wade's Tube Page: https://www.angelfire.com/vt/audio/
Waltzing Bear (Pro sound): http://www.waltzingbear.com/Schematics/

Altec and other pro audio: http://vintagewindings.com/products/ManualsCatalogs.html
Ampex (archive from 2016): https://web.archive.org/web/20161001024326/http:/www.ampex.com:80/hist-ref-doc-audio.html
Bang & Olufsen: https://beo.zone/media/files/
Bogen, a few:  (gone! archive): https://web.archive.org/web/20210812074906/https://makearadio.com/schematics/index.php
Dynaco: http://www.tubes4hifi.com/downloads.htm
Fisher: http://www.fisherconsoles.com/service%20owner%20manual%20list.html
H.H. Scott: (gone! - archive)  http://web.archive.org/web/20200505135105/http://hhscott.com/database/vhhs_00011.html
Marantz (archive from 2005): https://web.archive.org/web/20050103025945/http://www.dummyload.com/marantz/index.html
McIntosh: http://www.tubebooks.org/mcintosh_data.htm
Revox and Studer: https://www.reeltoreel.nl/studer/Public/Products/
Yamaha: https://usa.yamaha.com/products/contents/audio_visual/downloads/manuals/index.html

Communications

Boat Anchor Manual Archive: http://bama.edebris.com/manuals/
CQHam.ru manuals: http://www.cqham.ru/sch_eng.html
Hamanuals: http://www.hamanuals.com/miscmans.html
James Moorer's Boat Anchors: http://www.jamminpower.org/Boat%20anchors.html+
K4OZY's Boatanchor Manuals: http://jptronics.org/
KO4BB Manuals: http://www.ko4bb.com/getsimple/index.php?id=manuals
Mods.dk manuals: https://www.mods.dk/manual.php
One Electron, Ham: https://www.one-electron.com/Archives/Techs_FC/FC_Ham.html
One Electron, Military: https://www.one-electron.com/Archives/Techs_FC/FC_Military.html
RadioManual.eu: http://www.radiomanual.eu/
Repeater Builder: http://manuals.repeater-builder.com/

Collins: http://www.collinsradio.org/cca-collins-technical-archives/collins-radio-equipment-manuals/
Drake: http://www.hug-a-bug.com/manuals.htm
More Drake: http://www.wb4hfn.com/DRAKE/DrakeManuals.htm
Hallicrafters Repair & Rehab: https://wd0gof.com/hallicrafters-radio/repair-manuals/
Hammarlund: http://www.hammarlund.info/hamrmanu.html
ICOM current & legacy: http://www.icomamerica.com/en/downloads/
Kenwood: https://www.kenwood.com/usa/Support/Amateur_Radio/
MFJ (and a few others): https://mfjenterprises.com/pages/product-manuals
(Military) Radio Nerds: https://www.radionerds.com/
NJ7P Military and Tube Manuals: http://www.nj7p.org/Manuals/Manuals.php
TMC: https://www.tmchistory.org/tmc_manuals/tmc_manual_directory.htm
U.S. Navy: https://www.navy-radio.com/manuals-equip.htm
Yaesu: http://www.foxtango.org/ft-library/FT-Library/index.htm

Musical Instruments

Amps and effects: https://blueguitar.net/schems.htm
Ampage Schematics: https://www.ampage.org/schems/
Dr Tube (Netherlands): https://www.drtube.com/guitar-amp-schematics/
Duncan Amps: http://tdsl.duncanamps.com/schematics.php
Effects: http://www.generalguitargadgets.com/how-to-build-it/technical-help/schematics/
Guitar amps: http://guitarnucleus.net/resources-schematics.html
Guitar effects & pedals: https://www.freestompboxes.org/viewtopic.php?t=1295
Guitar effects: http://www.geofex.com/
Guitar and amp manuals (mainly user's manuals): https://archive.org/details/guitarmanuals
Mojotone has some schematics: https://ampwares.com/#
Prowess Amps: http://www.prowessamplifiers.com/schematics/
Schematic Heaven: https://schematicheaven.net/
Schematics.ca: http://www.schematics.ca/
The "Open Source" Guitar amp: https://ax84.com/archive/ax84.com/index.html
Tube Guitar amps: https://el34world.com/charts/TubeAmpSchematics.htm

Carvin: https://carvinaudio.com/pages/guitar-amp-schematics
Fender Field Guide: http://www.thevintagesound.com/ffg/
Hammond & Leslie: http://www.captain-foldback.com/Hammond_sub/hammond_schematics.htm
Magnatone: https://www.magnatoneamps.com/schematics.html
Univox: http://www.vintageunivox.com/schematics.html
Vox: https://www.korguk.com/voxcircuits/index.htm

Test Equipment

Bitsavers: http://bitsavers.informatik.uni-stuttgart.de/test_equipment/
Boat Anchor Manual Archive: http://bama.edebris.com/manuals/
Some British test equipmnet: http://www.thevalvepage.com/servdata/servdata.htm#Servicedata
Communications test equipment: http://www.repeater-builder.com/test-equipment/test-equipment-index.html
Ebaman: https://www.ebaman.com/index.php/remository/ELECTRONICS/Test-Equipment/
A few: https://www.qsl.net/n9zia/test/index.html
A few more: http://radiorestorer.com/downloads.html
Chris Grossman: https://chrisgrossman.com/manuals/
KO4BB Manuals: http://www.ko4bb.com/getsimple/index.php?id=manuals
Oscilloscopes: https://www.oscilloscopemuseum.org/
More: https://www.byan-roper.org/steve/manuals/

Anritsu / Wiltron: https://www.anritsu.com/en-US/test-measurement/support/downloads
B&K Precision: https://www.bkprecision.com/support/downloads/manuals.html
Fluke: https://www.fluke.com/en-us/support/manuals
General Radio: https://www.ietlabs.com/genradhistoricalsociety   More: http://jptronics.org/GR/index.html
Hameg: https://www.sm5cbw.se/hameg/index.htm
Hickok: https://www.stevenjohnson.com/hickok/index.html
hp Archive: http://hparchive.com/
hp / Agilent / Keysight: https://support.keysight.com/s/?language=en_US (Enter a model #, some vintage manuals)
hp Museum: https://www.kennethkuhn.com/hpmuseum/scans/
Kikusui: https: https://kikusui.co.jp/manuals/index_e.php
Kurt's hp manuals: https://xdevs.com/doc/HP_Agilent_Keysight/index.htm
Precision Tube Testers: http://oldradios.50webs.com/precision/
Simpson (slow): https://www.simpson260.com/
Supreme Tube Testers: http://stevenjohnson.com/supreme/tubetesters.htm
Tektronix: https://w140.com/tekwiki/wiki/
Telequipment: http://www.thevalvepage.com/servdata/testeq/telequip.htm

Misc. (multiple categories)

A bit of everything: https://elektrotanya.com/
And a bit more: https://www.manualslib.com/
And more: https://www.eserviceinfo.com/
And: https://www.download-service-manuals.com/en/index.php
And: https://www.opweb.de/english/home
4792 Military Manuals https://www.liberatedmanuals.com/all.mpl (Search with Ctrl-F)
Heath manuals: http://tubularelectronics.com/Heath_Manual_Collection/
Heathkit: https://www.vintage-radio.info/heathkit/index.htm
Heathkit of the Month - over 100 articles: https://www.w6ze.org/Heathkit/Heathkit_Index.html
A few kit schematics, more info: http://www.nostalgickitscentral.com/
Lost Manuals: https://www.lost-manuals.com/
Good luck with this one: https://manualsbrain.com/en/
Schematics Unlimited: https://www.schematicsunlimited.com/
Schematics for free: http://www.schematicsforfree.com/files/
3 Million manuals - good luck! : https://archive.org/details/manuals

Archive.org - Electronics books: https://archive.org/details/folkscanomy_electronics
Vintage Techncal Books: http://tubebooks.org/technical_books_online.htm

Where to Buy

Antique Wireless Association - surplus manuals: http://www.bit.ly/AWACQH
Artek: https://artekmanuals.com/
Data Pro (Heathkit): https://sc4.vom.com/d8/index.fwx?C=MANUALS
Manual Man: https://manualman.com/index.cfm
Military manuals: https://fairradio.com/manuals/
Radio Manuals: https://www.radiomanuals.com/
Sams Photofacts: https://www.samswebsite.com/
SMC Electronics: https://www.smcelectronics.com/samsmain.htm
Sphere Research: https://www.sphere.bc.ca/test/svcmanuals.html
Steve Johnson: https://stevenjohnson.com/
Surplus Sales: https://www.surplussales.com//Manuals/Manuals.html
Vintage Manuals (was W7FG): http://www.vintagemanuals.com/