Posted to FB group Vintage Transistor Radios Oct 7 and after.
\nYeah, it’s a bit confusing because the number of IF transformers is one more than the number of transistors.<\/p>\n
When you work on IFs, what do you use for alignment? I got Zenith Royal 500s that the previous owner apparently fiddled with the IF cores. I guess I need a sweep generator.<\/p>\n
Phillip Grace replied <\/p>\n
Yes, a simple fixed frequency generator is all that is needed, along with a DMM to read the DC voltage at the detector that drives the AGC circuitry. You can also use a generator with AM modulation along with the DMM set to AC to measure the audio level, or a scope. A sweep gen can come in handy when tuning sets that have wide bandwidth IF stages, but not necessary.
\nMe: Thank you for the informative replies. I read some docs online about alignment of AM radios. I have done FM alignment with a sweep generator. One of the radios tuned in 640 kHz with the tuning cap set at 780, so I retuned the LO coil to get it back down to 640. Another one looks like the cores on the IF cans have been messed with, so I think that may be the problem. But many of these have a bad volume control, so I’m going to work on those to get the audio stages working. Just getting the battery holder contacts restored is gonna take a lot of time. So I have to do a lot of TLC that will take time.<\/p>\n","protected":false},"excerpt":{"rendered":"
Posted to FB group Vintage Transistor Radios Oct 7 and after. Yeah, it’s a bit confusing because the number of IF transformers is one more than the number of transistors. When you work on IFs, what do you use for alignment? I got Zenith Royal 500s that the previous owner apparently fiddled with the IF <\/p>\n (Read More…)<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-12447","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/12447","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=12447"}],"version-history":[{"count":5,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/12447\/revisions"}],"predecessor-version":[{"id":12474,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/12447\/revisions\/12474"}],"wp:attachment":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=12447"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=12447"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=12447"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}