*388OPINION OF THE COURT
ROBERTS, Justice.Appellant James Alfred Banks was found guilty of voluntary manslaughter after a non-jury trial. Judgment of sentence of two to ten years imprisonment was imposed.
On this direct appeal appellant contends, through new counsel, that he did not make a knowing, voluntary and intelligent waiver of his right to trial by jury. He claims that the waiver was invalid because the court failed: (1) to advise appellant that he had a right to assist counsel on the selection of jurors; (2) to explain to appellant the nature of the charges against him; (3) to inquire whether appellant had received psychiatric treatment; and (4) to ask appellant if threats or promises induced his desire to waive jury trial.
We need not decide whether the colloquy here was adequate because appellant’s sole assignment of error was not raised by post-trial motions. The issue is not preserved for appellate review and, therefore, may not be the basis upon which relief can be granted in this appeal. See Commonwealth v. Carter, 463 Pa. 310, 344 A.2d 846 (1975); Commonwealth v. Reid, 458 Pa. 357, 326 A.2d 267 (1974); Commonwealth v. Mitchell, 461 Pa. 555, 337 A.2d 292 (1975); Commonwealth v. Bronaugh, 459 Pa. 634, 331 A.2d 171 (1975); Commonwealth v. Clair, 458 Pa. 418, 326 A.2d 272 (1974).
Judgment of sentence affirmed.