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The Yaesu FT-102 has acquired the reputation of being one of the best receivers ever made (as well as having the ability to put out a generous 150 watts of RF). Sadly, it also has an equally deserved reputation for troublesome relays. The design philosophy is good - relays are not as lossy as switching diodes in the receive path and don't suffer from the latter's intermod problems. However, Yaesu chose unsealed relays to do the job and time has taken it's toll. Nearly all FT-102 problems are due to contaminated or worn relay contacts.
A complete set of sealed relays will give the FT-102 a new lease of life and restore the joy of operating a "real" radio to the fortunate owner. Change them all while you have the radio on the bench - if one has started to give trouble, most of the others will surely follow. It's only a matter of time.
I publish this information in the hope that it may be of use to someone. Some additional parts information has been added at the bottom of the page.
Starting point is EB5AGV's excellent tutorial on the subject, which is essential reading for anyone contemplating this task.
RL05 on the RF Board is the most awkward to change because of the amount of dismantling involved. All the other relays can be changed without too much difficulty but some care is required. Modifications to the RF Board to accept a substitute for RL02 (as per EB5AGV) must be carried out, unless you wish to go to the expense of having the original gold plated (it can be done!).
I have listed below what I consider to be suitable relays for use in the FT-102 although I have borrowed heavily from EB5AGV's original document. Rapid Electronics in UK stock most of the Omron relays (as at Sept 2010), however these relays are now largely obsolete and future stocks may be limited. Indeed, recent inquiries indicate that the 24 volt relays are no longer available in small quantities in UK, although they may still be obtainable in USA with a minimum order of 25 pieces.
The cost of a set of nine relays was about £30 (incl shipping) from Rapid for Omron relays. Please note ** I DO NOT STOCK ANY RELAYS ** and you carry out any modifications at your own risk.