O suporte que tenho tido do grupo https://groups.io/g/Heathkit-Radios/ tem sido algo de fabuloso. Após ter dito que ia comprar um HW-101, vários utilizadores se prontificaram a ajudar com dicas excelentes.
Assim o consenso foi que a primeira coisa que devia fazer era limpar o rádio e verificar grounding das várias placas.
Deixo aqui um excerto do comentário do colega W5RKL acerca da limpeza:
The HW-100/101 and SB-100/101/102 all have the same 5 PC boards. The chassis’s on all of these radios are
made of “Aluminum”. The ground copper foil run around the bottom edge of each of the 5 PC boards must NOT
come in contact with the Aluminum chassis. Heathkit uses #3-40×3/8″ machine screws, #3 star lock washers,
and #3-40 machine nuts to mount the PC boards to the Aluminum chassis. During mounting a #3 star lock washer
is slide over the mounting screw between the PC board and the Aluminum chassis. The lock washer keeps the
PC board copper foil run “OFF” the Aluminum chassis. This also provides a separation between the chassis and
the PC board where, over time, a lot of corrosion/dirt/grease can inhabit that area and contaminate the PC board
grounds. To clean this area, simply loosening and tightening the mounting screws will not re-establish the PC board grounds. The area between the boards must be cleaned with cleaner and a soft brush slide under the board and use a scrubbing action to clean that area. Once the cleaning process is completed, generous amounts of canned or compressed air blown between the board and the chassis to remove the corrosion/dirt/grease. It may be necessary to repeat this process to remove all the corrosion/dirt/grease. Then tighten the mounting screws.The PC board mounting screws from Heathkit are made of steel and depending on the environment the radio was
subjected to, some/many of the mounting screws will rust and loosening may be difficult. New mounting screws,
star lock washers, and nuts can be obtain on eBay or other online sources. I buy them in qty’s of 100 or more
from eBay sellers.
Assim para limpar comecei com uma lata de ar comprimido para retirar o pó.
Comecei por baixo com álcool isopropilico e um pincel. limpei todas as placas. Os sitios mais teimosos foram limpos com uma cotonete.
Separei as placas do chassis e com o pincel limpei bem entre os 2, deixei secar e voltei a prender.
Após a limpeza inicial, verifiquei a continuidade do ground das placas com o chassis, para já está tudo ok. Próximo passo condensadores eletrolíticos.